docs: improve github labels by introducing "PR target" labels (#18436)
docs: improve github labels by introducing "PR target" labels (#18436)

I also renamed all "pr_*" lables to "PR *" lables, removed obsolete
"chore" label, and added docs label.
filipesilva/angular,angular-indonesia/angular,mhevery/angular,angularbrasil/angular,nosovk/angular,Brocco/angular,LucasSloan/angular,ocombe/angular,jonrimmer/angular,mgol/angular,blesh/angular,manekinekko/angular,meeroslav/angular,juristr/angular,manekinekko/angular,wKoza/angular,mzgol/angular,kara/angular,dtoroshin/n2oDoc,alexeagle/angular,kegluneq/angular,hansl/angular,gdi2290/angular,mgol/angular,vicb/angular,angular-indonesia/angular,ghetolay/angular,mgiambalvo/angular,alexeagle/angular,hansl/angular,ultrasonicsoft/angular,juleskremer/angular,kara/angular,kegluneq/angular,ghetolay/angular,vikerman/angular,mhevery/angular,meeroslav/angular,cironunes/angular,mzgol/angular,JiaLiPassion/angular,mgol/angular,gkalpak/angular,vicb/angular,snaptech/angular,kegluneq/angular,juristr/angular,smartm0use/angular,brandonroberts/angular,trshafer/angular,matsko/angular,dsebastien/angular,sarunint/angular,petebacondarwin/angular,gnomeontherun/angular,robwormald/angular,kara/angular,kara/angular,mhevery/angular,tbosch/angular,ultrasonicsoft/angular,brandonroberts/angular,wKoza/angular,ocombe/angular,alxhub/angular,robwormald/angular,NathanWalker/angular,dsebastien/angular,dsebastien/angular,mgechev/angular,mlaval/angular,ghetolay/angular,ocombe/angular,ocombe/angular,hansl/angular,robwormald/angular,snaptech/angular,meeroslav/angular,juristr/angular,tbosch/angular,rkirov/angular,NathanWalker/angular,heathkit/angular,heathkit/angular,ValtoFrameworks/Angular-2,wKoza/angular,sarunint/angular,rkirov/angular,blesh/angular,mgiambalvo/angular,mgechev/angular,hansl/angular,heathkit/angular,aboveyou00/angular,nosovk/angular,gnomeontherun/angular,juleskremer/angular,kara/angular,filipesilva/angular,wKoza/angular,pk-karthik/framework-js-angular,LucasSloan/angular,IgorMinar/angular,kegluneq/angular,ultrasonicsoft/angular,nosovk/angular,gdi2290/angular,IdeaBlade/angular,cironunes/angular,mgol/angular,juristr/angular,IgorMinar/angular,mzgol/angular,brandonroberts/angular,petebacondarwin/angular,angular/angular,rkirov/angular,NathanWalker/angular,kegluneq/angular,ghetolay/angular,StephenFluin/angular,gdi2290/angular,snaptech/angular,sarunint/angular,chuckjaz/angular,angular/angular,alexeagle/angular,ocombe/angular,kegluneq/angular,mhevery/angular,IgorMinar/angular,dtoroshin/n2oDoc,Toxicable/angular,alxhub/angular,dtoroshin/n2oDoc,LucasSloan/angular,jasonaden/angular,angular/angular,ultrasonicsoft/angular,mgiambalvo/angular,Toxicable/angular,blesh/angular,nosovk/angular,manekinekko/angular,mprobst/angular,manekinekko/angular,mgiambalvo/angular,shairez/angular,jonrimmer/angular,Toxicable/angular,petebacondarwin/angular,dsebastien/angular,matsko/angular,Brocco/angular,alexeagle/angular,trshafer/angular,jasonaden/angular,gkalpak/angular,aboveyou00/angular,jasonaden/angular,NathanWalker/angular,angularbrasil/angular,Brocco/angular,gnomeontherun/angular,hansl/angular,trshafer/angular,tbosch/angular,jonrimmer/angular,alxhub/angular,JiaLiPassion/angular,manekinekko/angular,pk-karthik/framework-js-angular,mprobst/angular,smartm0use/angular,mprobst/angular,robwormald/angular,brandonroberts/angular,petebacondarwin/angular,heathkit/angular,IgorMinar/angular,rkirov/angular,ultrasonicsoft/angular,ValtoFrameworks/Angular-2,shairez/angular,mgechev/angular,jasonaden/angular,wKoza/angular,StephenFluin/angular,angularbrasil/angular,gjungb/angular,petebacondarwin/angular,jasonaden/angular,mzgol/angular,cironunes/angular,juleskremer/angular,vikerman/angular,trshafer/angular,tbosch/angular,juristr/angular,angular-indonesia/angular,angularbrasil/angular,gjungb/angular,brandonroberts/angular,vicb/angular,Toxicable/angular,jonrimmer/angular,Brocco/angular,cironunes/angular,pk-karthik/framework-js-angular,mprobst/angular,petebacondarwin/angular,ultrasonicsoft/angular,mzgol/angular,ValtoFrameworks/Angular-2,vsavkin/angular,IdeaBlade/angular,aboveyou00/angular,smartm0use/angular,vikerman/angular,rkirov/angular,aboveyou00/angular,IdeaBlade/angular,juleskremer/angular,trshafer/angular,smartm0use/angular,nosovk/angular,filipesilva/angular,shairez/angular,mhevery/angular,JiaLiPassion/angular,LucasSloan/angular,pk-karthik/framework-js-angular,gkalpak/angular,smartm0use/angular,gnomeontherun/angular,gdi2290/angular,StephenFluin/angular,juristr/angular,blesh/angular,IdeaBlade/angular,blesh/angular,sarunint/angular,vicb/angular,mgechev/angular,vicb/angular,angular/angular,angularbrasil/angular,Toxicable/angular,brandonroberts/angular,gdi2290/angular,shairez/angular,matsko/angular,sarunint/angular,kara/angular,chuckjaz/angular,IdeaBlade/angular,StephenFluin/angular,Brocco/angular,meeroslav/angular,mlaval/angular,mlaval/angular,LucasSloan/angular,jonrimmer/angular,mprobst/angular,chuckjaz/angular,NathanWalker/angular,jasonaden/angular,ValtoFrameworks/Angular-2,manekinekko/angular,StephenFluin/angular,shairez/angular,mgol/angular,cironunes/angular,mgol/angular,mlaval/angular,vsavkin/angular,vikerman/angular,pk-karthik/framework-js-angular,gjungb/angular,dtoroshin/n2oDoc,Brocco/angular,juleskremer/angular,robwormald/angular,mgiambalvo/angular,snaptech/angular,aboveyou00/angular,IgorMinar/angular,robwormald/angular,alxhub/angular,mlaval/angular,vikerman/angular,vsavkin/angular,IgorMinar/angular,vikerman/angular,vicb/angular,chuckjaz/angular,Toxicable/angular,cironunes/angular,alxhub/angular,matsko/angular,mhevery/angular,NathanWalker/angular,vsavkin/angular,vsavkin/angular,LucasSloan/angular,alexeagle/angular,mprobst/angular,filipesilva/angular,ValtoFrameworks/Angular-2,gkalpak/angular,meeroslav/angular,heathkit/angular,wKoza/angular,dsebastien/angular,filipesilva/angular,snaptech/angular,mgechev/angular,JiaLiPassion/angular,matsko/angular,ocombe/angular,snaptech/angular,angular-indonesia/angular,tbosch/angular,trshafer/angular,gdi2290/angular,heathkit/angular,hansl/angular,rkirov/angular,gjungb/angular,jonrimmer/angular,sarunint/angular,dtoroshin/n2oDoc,ghetolay/angular,aboveyou00/angular,angularbrasil/angular,mzgol/angular,gjungb/angular,chuckjaz/angular,chuckjaz/angular,alexeagle/angular,dsebastien/angular