fix(core): make .toRx() return Subject
fix(core): make .toRx() return Subject

this was broken in the original great RxNext migration.
fixes #4521

Closes #4540

hankduan/angular,robwormald/angular,vandres/angular,trshafer/angular,jasonaden/angular,tapas4java/angular,mhegazy/angular,ttowncompiled/angular,huoxudong125/angular,dsebastien/angular,youdz/angular,tamascsaba/angular,jteplitz602/angular,vikerman/angular,StephenFluin/angular,heathkit/angular,mprobst/angular,huoxudong125/angular,basvandenheuvel/angular,laskoviymishka/angular,tamascsaba/angular,ocombe/angular,trshafer/angular,chajath/angular,yjbanov/angular,tapas4java/angular,mixed/angular,mhevery/angular,martinmcwhorter/angular,e-schultz/angular,Tragetaschen/angular,e-hein/angular,vicb/angular,snaptech/angular,m18/angular,snaptech/angular,trshafer/angular,blesh/angular,snaptech/angular,sjtrimble/angular,angularbrasil/angular,vamsivarikuti/angular,hansl/angular,alexeagle/angular,mprobst/angular,wesleycho/angular,nosovk/angular,pk-karthik/framework-js-angular,yjbanov/angular,kevinmerckx/angular,meeroslav/angular,JSMike/angular,hansl/angular,zhura/angular,rjamet/angular,yanivefraim/angular,gkalpak/angular,mixed/angular,heathkit/angular,tapas4java/angular,mlynch/angular,pkozlowski-opensource/angular,jelbourn/angular,JiaLiPassion/angular,kylecordes/angular,LucasSloan/angular,LucasSloan/angular,mgol/angular,sarunint/angular,zhura/angular,jelbourn/angular,angular-indonesia/angular,SaltyDH/angular,markharding/angular,sjtrimble/angular,IdeaBlade/angular,nosovk/angular,kara/angular,petebacondarwin/angular,mprobst/angular,JSMike/angular,hdeshev/angular,shairez/angular,chajath/angular,diestrin/angular,hpinsley/angular,dejour/angular,juristr/angular,not-for-me/angular,mhevery/angular,zolfer/angular,cironunes/angular,dejour/angular,kevinmerckx/angular,zhura/angular,aboveyou00/angular,Brocco/angular,alxhub/angular,ochafik/angular,brandonroberts/angular,hterkelsen/angular,gjungb/angular,mlynch/angular,manekinekko/angular,Toxicable/angular,gilamran/angular,angularbrasil/angular,petebacondarwin/angular,shuhei/angular,cironunes/angular,alfonso-presa/angular,bkyarger/angular,rkirov/angular,huoxudong125/angular,mgiambalvo/angular,trshafer/angular,ValtoFrameworks/Angular-2,markharding/angular,royling/angular,AlmogShaul/angular,UIUXEngineering-Forks/angular,alexcastillo/angular,SekibOmazic/angular,choeller/angular,vsavkin/angular,naomiblack/angular,IdeaBlade/angular,angular/angular,dejour/angular,jonrimmer/angular,brandonroberts/angular,nosovk/angular,pk-karthik/framework-js-angular,mgiambalvo/angular,erictsangx/angular,wKoza/angular,AlmogShaul/angular,gjungb/angular,ScottSWu/angular,bkyarger/angular,hannahhoward/angular,pkozlowski-opensource/angular,hpinsley/angular,SekibOmazic/angular,ghetolay/angular,rkirov/angular,angularbrasil/angular,chuckjaz/angular,dsebastien/angular,SaltyDH/angular,chadqueen/angular,mdegoo/angular,laco0416/angular,mgechev/angular,ollie314/angular,dsebastien/angular,UIUXEngineering-Forks/angular,LucasSloan/angular,chalin/angular,IAPark/angular,youdz/angular,robwormald/angular,cironunes/angular,jasonaden/angular,IdeaBlade/angular,laskoviymishka/angular,bkyarger/angular,hterkelsen/angular,not-for-me/angular,laskoviymishka/angular,TedSander/angular,zhura/angular,alexcastillo/angular,rbevers/angular,alfonso-presa/angular,vikerman/angular,erictsangx/angular,zhura/angular,dmitriz/angular,awerlang/angular,TedSander/angular,tyleranton/angular,cexbrayat/angular,mlynch/angular,jteplitz602/angular,tycho01/angular,ericmartinezr/angular,ocombe/angular,chrisse27/angular,vandres/angular,gjungb/angular,cassand/angular,souldreamer/angular,chadqueen/angular,royling/angular,souvikbasu/angular,JanStureNielsen/angular,cassand/angular,angular/angular,Tragetaschen/angular,weswigham/angular,jhonmike/angular,IAPark/angular,dtoroshin/n2oDoc,Mathou54/angular,gilamran/angular,jasonaden/angular,jonrimmer/angular,Tragetaschen/angular,zolfer/angular,IgorMinar/angular,cexbrayat/angular,alfonso-presa/angular,hterkelsen/angular,alexcastillo/angular,domusofsail/angular,cyrilgandon/angular,shirish87/angular,antonmoiseev/angular,angularbrasil/angular,mdegoo/angular,alexcastillo/angular,panuruj/angular,gkalpak/angular,zolfer/angular,shirish87/angular,ochafik/angular,souldreamer/angular,erictsangx/angular,heathkit/angular,alexpods/angular,alfonso-presa/angular,StacyGay/angular,mgiambalvo/angular,ericmartinezr/angular,cyrilgandon/angular,panuruj/angular,mgechev/angular,cyrilgandon/angular,diestrin/angular,cassand/angular,jonrimmer/angular,kwalrath/angular,meeroslav/angular,ValtoFrameworks/Angular-2,souldreamer/angular,vinagreti/angular,kegluneq/angular,xcaliber-tech/angular,wesleycho/angular,juleskremer/angular,nosovk/angular,sjtrimble/angular,gionkunz/angular,StacyGay/angular,mprobst/angular,dydek/angular,hdeshev/angular,JanStureNielsen/angular,dejour/angular,templth/angular,Brocco/angular,cyrilgandon/angular,petebacondarwin/angular,TedSander/angular,laco0416/angular,kara/angular,micmro/angular,mlynch/angular,chajath/angular,tolemac/angular,markharding/angular,graveto/angular,alexcastillo/angular,cironunes/angular,souvikbasu/angular,Toxicable/angular,juleskremer/angular,rkirov/angular,weswigham/angular,heathkit/angular,IAPark/angular,m18/angular,martinmcwhorter/angular,matsko/angular,graveto/angular,petebacondarwin/angular,souldreamer/angular,dejour/angular,mlynch/angular,xcaliber-tech/angular,graveto/angular,wKoza/angular,yanivefraim/angular,smartm0use/angular,souvikbasu/angular,dydek/angular,kylecordes/angular,dtoroshin/n2oDoc,diestrin/angular,jonrimmer/angular,kara/angular,panuruj/angular,dtoroshin/n2oDoc,tycho01/angular,manekinekko/angular,epotvin/angular,shairez/angular,mgiambalvo/angular,mgechev/angular,robwormald/angular,Tragetaschen/angular,rbevers/angular,vsavkin/angular,ttowncompiled/angular,dydek/angular,jteplitz602/angular,NathanWalker/angular,chrisse27/angular,shirish87/angular,antonmoiseev/angular,vikerman/angular,e-schultz/angular,shairez/angular,ScottSWu/angular,mixed/angular,e-hein/angular,kegluneq/angular,martinmcwhorter/angular,willseeyou/angular,ocombe/angular,vamsivarikuti/angular,jesperronn/angular,blesh/angular,SaltyDH/angular,pk-karthik/framework-js-angular,martinmcwhorter/angular,itamark/angular,jelbourn/angular,naomiblack/angular,mixed/angular,ttowncompiled/angular,shirish87/angular,mgol/angular,mixed/angular,petebacondarwin/angular,tycho01/angular,ghetolay/angular,LucasSloan/angular,sarunint/angular,graveto/angular,chuckjaz/angular,StacyGay/angular,NathanWalker/angular,asnowwolf/angular,zolfer/angular,Mathou54/angular,e-hein/angular,yanivefraim/angular,ollie314/angular,filipesilva/angular,rbevers/angular,UIUXEngineering/angular,chadqueen/angular,kwalrath/angular,mprobst/angular,StephenFluin/angular,Tragetaschen/angular,wKoza/angular,gdi2290/angular,graveto/angular,souldreamer/angular,UIUXEngineering/angular,vikerman/angular,pkozlowski-opensource/angular,templth/angular,wesleycho/angular,angular-indonesia/angular,shuhei/angular,StephenFluin/angular,ocombe/angular,awerlang/angular,filipesilva/angular,SaltyDH/angular,ultrasonicsoft/angular,chuckjaz/angular,ScottSWu/angular,micmro/angular,sarunint/angular,pkozlowski-opensource/angular,mlaval/angular,gnomeontherun/angular,matsko/angular,kevinmerckx/angular,vikerman/angular,mgechev/angular,epotvin/angular,asnowwolf/angular,ochafik/angular,alxhub/angular,robwormald/angular,dsebastien/angular,vandres/angular,tyleranton/angular,m18/angular,xcaliber-tech/angular,shirish87/angular,aboveyou00/angular,chrisse27/angular,hansl/angular,ValtoFrameworks/Angular-2,gilamran/angular,UIUXEngineering-Forks/angular,vsavkin/angular,mgol/angular,mzgol/angular,youdz/angular,UIUXEngineering-Forks/angular,asnowwolf/angular,laskoviymishka/angular,Flounn/angular,micmro/angular,gionkunz/angular,brandonroberts/angular,alamgird/angular,huoxudong125/angular,hankduan/angular,erictsangx/angular,chrisse27/angular,kylecordes/angular,Flounn/angular,hankduan/angular,cironunes/angular,tapas4java/angular,shuhei/angular,rjamet/angular,mlynch/angular,mhegazy/angular,juristr/angular,Symagic/angular,hankduan/angular,erictsangx/angular,cexbrayat/angular,epotvin/angular,tolemac/angular,jteplitz602/angular,alexeagle/angular,tolemac/angular,ollie314/angular,dydek/angular,wKoza/angular,zhura/angular,jelbourn/angular,tyleranton/angular,jelbourn/angular,smartm0use/angular,smartm0use/angular,domusofsail/angular,IAPark/angular,juristr/angular,asnowwolf/angular,blesh/angular,tbosch/angular,ericmartinezr/angular,tapas4java/angular,Mathou54/angular,jesperronn/angular,asnowwolf/angular,tycho01/angular,rkirov/angular,bkyarger/angular,AlmogShaul/angular,smartm0use/angular,hankduan/angular,ericmartinezr/angular,hannahhoward/angular,mikeybyker/angular,mikeybyker/angular,juristr/angular,gionkunz/angular,choeller/angular,filipesilva/angular,mgol/angular,blesh/angular,NathanWalker/angular,kara/angular,dmitriz/angular,chajath/angular,hannahhoward/angular,tyleranton/angular,Brocco/angular,not-for-me/angular,hansl/angular,Brocco/angular,micmro/angular,tyleranton/angular,basvandenheuvel/angular,mhegazy/angular,sjtrimble/angular,Symagic/angular,yanivefraim/angular,sarunint/angular,erictsangx/angular,trshafer/angular,chajath/angular,Toxicable/angular,StephenFluin/angular,ScottSWu/angular,gionkunz/angular,Symagic/angular,gilamran/angular,dtoroshin/n2oDoc,hannahhoward/angular,ochafik/angular,shairez/angular,kara/angular,martinmcwhorter/angular,choeller/angular,vicb/angular,pk-karthik/framework-js-angular,weswigham/angular,alamgird/angular,jesperronn/angular,e-hein/angular,mprobst/angular,UIUXEngineering/angular,sarunint/angular,dsebastien/angular,robwormald/angular,shuhei/angular,ghetolay/angular,kegluneq/angular,mzgol/angular,SaltyDH/angular,kylecordes/angular,tamascsaba/angular,graveto/angular,e-schultz/angular,tamascsaba/angular,vinagreti/angular,sjtrimble/angular,dmitriz/angular,laskoviymishka/angular,ScottSWu/angular,gjungb/angular,Toxicable/angular,matsko/angular,alfonso-presa/angular,JSMike/angular,LucasSloan/angular,hankduan/angular,alexeagle/angular,yjbanov/angular,tbosch/angular,vinagreti/angular,rbevers/angular,StephenFluin/angular,Symagic/angular,laco0416/angular,Symagic/angular,cexbrayat/angular,IgorMinar/angular,chalin/angular,e-schultz/angular,antonmoiseev/angular,domusofsail/angular,ochafik/angular,kegluneq/angular,markharding/angular,m18/angular,meeroslav/angular,hansl/angular,domusofsail/angular,naomiblack/angular,mlaval/angular,IdeaBlade/angular,Symagic/angular,cyrilgandon/angular,kwalrath/angular,epotvin/angular,mixed/angular,UIUXEngineering/angular,choeller/angular,Mathou54/angular,jesperronn/angular,jhonmike/angular,manekinekko/angular,gionkunz/angular,mgiambalvo/angular,tycho01/angular,alexeagle/angular,templth/angular,cassand/angular,StacyGay/angular,vikerman/angular,chadqueen/angular,hpinsley/angular,vamsivarikuti/angular,juristr/angular,UIUXEngineering-Forks/angular,vicb/angular,GistIcon/angular,tyleranton/angular,shuhei/angular,snaptech/angular,souldreamer/angular,m18/angular,heathkit/angular,vsavkin/angular,chalin/angular,vicb/angular,jasonaden/angular,mdegoo/angular,Toxicable/angular,micmro/angular,gdi2290/angular,angular/angular,templth/angular,JSMike/angular,panuruj/angular,mhegazy/angular,panuruj/angular,SekibOmazic/angular,jesperronn/angular,shuhei/angular,kevinmerckx/angular,hpinsley/angular,ocombe/angular,weswigham/angular,alexpods/angular,SekibOmazic/angular,filipesilva/angular,alexcastillo/angular,weswigham/angular,JanStureNielsen/angular,brandonroberts/angular,mdegoo/angular,LucasSloan/angular,tamascsaba/angular,aboveyou00/angular,naomiblack/angular,jonrimmer/angular,gkalpak/angular,cironunes/angular,chalin/angular,tbosch/angular,kevinmerckx/angular,rkirov/angular,GistIcon/angular,angular-indonesia/angular,hpinsley/angular,markharding/angular,zolfer/angular,jhonmike/angular,awerlang/angular,mlaval/angular,robertmesserle/angular,sarunint/angular,yanivefraim/angular,tbosch/angular,dmitriz/angular,hdeshev/angular,gionkunz/angular,mdegoo/angular,rjamet/angular,cassand/angular,tolemac/angular,heathkit/angular,GistIcon/angular,royling/angular,jteplitz602/angular,IgorMinar/angular,ttowncompiled/angular,ScottSWu/angular,alexpods/angular,ultrasonicsoft/angular,Brocco/angular,ochafik/angular,mdegoo/angular,jasonaden/angular,TedSander/angular,hdeshev/angular,vinagreti/angular,pkozlowski-opensource/angular,Brocco/angular,brandonroberts/angular,wKoza/angular,alexeagle/angular,epotvin/angular,brandonroberts/angular,micmro/angular,angular/angular,souvikbasu/angular,JanStureNielsen/angular,chadqueen/angular,tolemac/angular,dmitriz/angular,vicb/angular,robwormald/angular,juleskremer/angular,choeller/angular,gnomeontherun/angular,mikeybyker/angular,JiaLiPassion/angular,Mathou54/angular,huoxudong125/angular,gdi2290/angular,jelbourn/angular,yjbanov/angular,e-hein/angular,tycho01/angular,mgol/angular,snaptech/angular,JSMike/angular,tbosch/angular,gilamran/angular,hterkelsen/angular,JiaLiPassion/angular,vinagreti/angular,itamark/angular,youdz/angular,antonmoiseev/angular,not-for-me/angular,matsko/angular,laco0416/angular,GistIcon/angular,epotvin/angular,angularbrasil/angular,jhonmike/angular,antonmoiseev/angular,alamgird/angular,mhevery/angular,markharding/angular,mhevery/angular,mhevery/angular,hannahhoward/angular,robertmesserle/angular,mlaval/angular,vamsivarikuti/angular,juleskremer/angular,chuckjaz/angular,mlaval/angular,angularbrasil/angular,gkalpak/angular,kara/angular,aboveyou00/angular,alexpods/angular,AlmogShaul/angular,TedSander/angular,meeroslav/angular,Flounn/angular,robertmesserle/angular,ericmartinezr/angular,rbevers/angular,robertmesserle/angular,basvandenheuvel/angular,wKoza/angular,robertmesserle/angular,basvandenheuvel/angular,UIUXEngineering/angular,ttowncompiled/angular,JanStureNielsen/angular,vsavkin/angular,basvandenheuvel/angular,alexpods/angular,willseeyou/angular,TedSander/angular,ultrasonicsoft/angular,xcaliber-tech/angular,nosovk/angular,bkyarger/angular,tapas4java/angular,juleskremer/angular,laco0416/angular,dsebastien/angular,kegluneq/angular,basvandenheuvel/angular,e-schultz/angular,gjungb/angular,ultrasonicsoft/angular,hdeshev/angular,chuckjaz/angular,blesh/angular,ericmartinezr/angular,mzgol/angular,aboveyou00/angular,hdeshev/angular,choeller/angular,alexpods/angular,alexeagle/angular,yjbanov/angular,alfonso-presa/angular,IAPark/angular,Flounn/angular,antonmoiseev/angular,kwalrath/angular,e-schultz/angular,templth/angular,ollie314/angular,itamark/angular,itamark/angular,ghetolay/angular,jasonaden/angular,StacyGay/angular,chuckjaz/angular,gdi2290/angular,kwalrath/angular,gnomeontherun/angular,hannahhoward/angular,rjamet/angular,youdz/angular,StacyGay/angular,Flounn/angular,kegluneq/angular,ollie314/angular,NathanWalker/angular,ttowncompiled/angular,willseeyou/angular,hterkelsen/angular,gnomeontherun/angular,petebacondarwin/angular,JiaLiPassion/angular,dydek/angular,mzgol/angular,awerlang/angular,hpinsley/angular,jonrimmer/angular,ultrasonicsoft/angular,xcaliber-tech/angular,mgol/angular,bkyarger/angular,dmitriz/angular,Tragetaschen/angular,NathanWalker/angular,mikeybyker/angular,IgorMinar/angular,willseeyou/angular,mzgol/angular,cassand/angular,NathanWalker/angular,IgorMinar/angular,kylecordes/angular,wesleycho/angular,mhegazy/angular,diestrin/angular,willseeyou/angular,royling/angular,souvikbasu/angular,chadqueen/angular,wesleycho/angular,mikeybyker/angular,vamsivarikuti/angular,itamark/angular,youdz/angular,alamgird/angular,matsko/angular,smartm0use/angular,IAPark/angular,mhevery/angular,jteplitz602/angular,rbevers/angular,mgechev/angular,manekinekko/angular,ocombe/angular,alamgird/angular,robertmesserle/angular,weswigham/angular,tamascsaba/angular,yanivefraim/angular,vandres/angular,mzgol/angular,alxhub/angular,m18/angular,yjbanov/angular,martinmcwhorter/angular,ValtoFrameworks/Angular-2,filipesilva/angular,GistIcon/angular,royling/angular,ghetolay/angular,kevinmerckx/angular,aboveyou00/angular,IdeaBlade/angular,hterkelsen/angular,mhegazy/angular,dtoroshin/n2oDoc,snaptech/angular,jhonmike/angular,GistIcon/angular,gdi2290/angular,hansl/angular,vicb/angular,SekibOmazic/angular,alxhub/angular,awerlang/angular,naomiblack/angular,UIUXEngineering-Forks/angular,chrisse27/angular,kylecordes/angular,cyrilgandon/angular,SekibOmazic/angular,trshafer/angular,pk-karthik/framework-js-angular,huoxudong125/angular,zolfer/angular,IgorMinar/angular,rkirov/angular,wesleycho/angular,angular-indonesia/angular,AlmogShaul/angular,laco0416/angular,shairez/angular,jhonmike/angular,manekinekko/angular,shirish87/angular,juristr/angular,ultrasonicsoft/angular,willseeyou/angular,Toxicable/angular,gdi2290/angular,not-for-me/angular,gilamran/angular,manekinekko/angular,domusofsail/angular,tolemac/angular,alxhub/angular,ValtoFrameworks/Angular-2,vandres/angular,meeroslav/angular,cexbrayat/angular