Improve key specific bash subcompletions
Improve key specific bash subcompletions

The obscure `case "${words[$cword-2]}$prev=" in` idiom is no
longer used for key specific completions in options with map values.

The `__docker_map_key_of_current_option()` function does a much
better job.

Signed-off-by: Harald Albers <64b2b6d12bfe4baae7dad3d018f8cbf6b0e7a044@albersweb.de>

hqhq/moby,asbjornenge/docker,YujiOshima/docker,jimjag/docker,sarnautov/moby,OnePaaS/docker,sanjeo/docker,jimjag/docker,tophj-ibm/moby,nalind/docker,erikh/docker,justyntemme/docker,gnailuy/docker,Microsoft/docker,anweiss/docker.github.io,errordeveloper/docker,ColinHebert/docker,tagomoris/docker,sfsmithcha/docker,denverdino/docker.github.io,wenchma/docker,darrenstahlmsft/docker,gjaskiewicz/moby,coolljt0725/docker,hustcat/docker,whuwxl/docker,dccurtis/docker,toli/docker,hypriot/docker,unclejack/docker,jhorwit2/docker,trebonian/docker,coreos/docker,docker/docker.github.io,rremer/moby,sheimi/docker,phiroict/docker,sallyom/docker,scollier/docker,carolfh/docker,upmio/docker,tophj-ibm/moby,resin-io/docker,kerneltime/docker,zhangjianfnst/docker,johnstep/docker.github.io,troy0820/docker.github.io,hqhq/moby,denverdino/denverdino.github.io,cloudflare/docker,PatrickLang/moby,aidanhs/docker,mstanleyjones/docker,dccurtis/docker,dperny/docker,jwhonce/docker,ripcurld0/moby,thaJeztah/docker,Mashimiao/docker,tpounds/docker,ColinHebert/docker,dsau/docker,rhardih/docker,docker/docker.github.io,michael-holzheu/docker,sfsmithcha/docker,trebonian/docker,luxas/docker,endophage/docker,jzwlqx/denverdino.github.io,rhatdan/docker,DoraALin/docker,stevvooe/docker,sanjeo/docker,Mokolea/docker,sean-jc/docker,anujbahuguna/docker,joaofnfernandes/docker.github.io,BSWANG/denverdino.github.io,Shopify/docker,noironetworks/docker,miminar/docker,aidanhs/docker,inatatsu/docker,jc-m/docker,bonczj/moby-json-file-logger,johnstep/moby-moby,jimjag/docker,shubheksha/docker.github.io,splunk/docker,JimGalasyn/docker.github.io,rkazak/docker,JimGalasyn/docker.github.io,inatatsu/docker,gschaetz/moby,containers/storage,xuxinkun/docker,medallia/docker,anweiss/docker.github.io,lixiaobing10051267/docker,KingEmet/docker,jameszhan/docker,danyalKhaliq10p/moby,justyntemme/docker,ivansaracino/docker,phiroict/docker,shin-/docker.github.io,hustcat/docker,alfred-landrum/docker,madhanrm/docker,joaofnfernandes/docker.github.io,YujiOshima/docker,Ramzec/docker,diogomonica/docker,DoraALin/docker,scollier/docker,LaynePeng/docker,mtrmac/docker,flavio/docker,jimjag/docker,stainboy/docker,yongtang/docker,denverdino/docker.github.io,Ramzec/docker,eskaaren/docker,coolljt0725/docker,thtanaka/docker,sterchelen/docker,konstruktoid/docker-upstream,ailispaw/docker,AkihiroSuda/docker,naveed-jamil-tenpearls/moby,ripcurld0/moby,whuwxl/docker,gschaetz/moby,stainboy/docker,catinthesky/docker,tpounds/docker,Ramzec/docker,ffoysal/docker,rillig/docker.github.io,cnaize/docker,docker-zh/docker.github.io,shin-/docker.github.io,charleszheng44/moby,nawawi/docker,mixja/docker,projectatomic/docker,estesp/docker,portworx/docker,bonczj/moby-json-file-logger,ndeloof/docker,sfsmithcha/docker,zhangjianfnst/docker,14rcole/docker,sean-jc/docker,darrenstahlmsft/docker,cyli/docker,noxiouz/docker,charleswhchan/docker,anweiss/docker.github.io,jecarey/docker,kojiromike/docker,AkihiroSuda/docker,sanscontext/docker.github.io,q384566678/docker,moxiegirl/docker,sallyom/docker,shishir-a412ed/docker,gao-feng/docker,sanscontext/docker.github.io,yummypeng/docker,resin-io/docker,lixiaobing1/docker,joeuo/docker.github.io,amatsus/docker,naveed-jamil-tenpearls/moby,sunyuan3/docker,BSWANG/denverdino.github.io,londoncalling/docker.github.io,prertik/docker,aduermael/docker.github.io,q384566678/docker,rillig/docker.github.io,tonistiigi/docker,konstruktoid/docker-1,rhatdan/docker,flavio/docker,BSWANG/denverdino.github.io,jongiddy/docker,crosbymichael/docker,dperny/docker,ivansaracino/docker,michelvocks/docker,laijs/docker,harche/docker,shishir-a412ed/docker,vijaykilari/docker,darrenstahlmsft/moby,shin-/docker.github.io,gigidwan/docker,vijaykilari/docker,icecrime/docker,nawawi/docker,PatrickLang/moby,shhsu/docker,akira-baruah/docker,anujbahuguna/docker,laijs/docker,contiv/docker,HuKeping/docker,duglin/docker,mtanlee/docker,ailispaw/docker,flavio/docker,mixja/docker,icecrime/docker,menglingwei/denverdino.github.io,cr7pt0gr4ph7/docker,endophage/docker,londoncalling/docker.github.io,xiekeyang/docker,YujiOshima/docker,icaoweiwei/docker,bfirsh/docker,haveatry/docker,konstruktoid/docker-1,danyalKhaliq10p/moby,shin-/docker.github.io,paralin/docker,harche/docker,davinashreddy/docker,troy0820/docker.github.io,dnephin/docker,konstruktoid/docker-upstream,raja-sami-10p/moby,tmp6154/docker,rancher/docker,estesp/docker,cyphar/docker,phiroict/docker,trebonian/docker,vijaykilari/docker,ripcurld0/moby,kolyshkin/moby,allencloud/docker,kunalkushwaha/docker,moul/docker,maxamillion/docker,JMesser81/docker,rhatdan/storage,joeuo/docker.github.io,mtrmac/docker,YuPengZTE/docker,stainboy/docker,isubuz/docker,JMesser81/docker,shubheksha/docker.github.io,srust/docker,geekylucas/docker,nguyentm83/docker,konstruktoid/docker-1,pecameron/docker,moxiegirl/docker,rhardih/docker,scotttlin/docker,kunalkushwaha/docker,PatrickLang/moby,menglingwei/denverdino.github.io,JimGalasyn/docker.github.io,gdevillele/docker.github.io,harche/docker,michael-holzheu/docker,liaoqingwei/docker,solganik/docker,xiaods/docker,bearstech/moby,13W/docker,projectatomic/docker,bluebreezecf/docker,mahak/docker,wenchma/docker,13W/docker,mtrmac/docker,msabansal/docker,abhinavdahiya/docker,sanscontext/docker.github.io,errordeveloper/docker,bearstech/moby,alexisbellido/docker.github.io,dsau/docker,yummypeng/docker,menglingwei/denverdino.github.io,contiv/docker,yosifkit/docker,14rcole/docker,LaynePeng/docker,bdwill/docker.github.io,darrenstahlmsft/moby,kunalkushwaha/docker,ivansaracino/docker,contiv/docker,johnstep/moby-moby,konstruktoid/docker-upstream,yasiramin10p/moby,joeuo/docker.github.io,DoraALin/docker,mkumatag/docker,bfirsh/docker,mike1729/docker,xuxinkun/docker,gdevillele/docker.github.io,BenHall/docker,willmtemple/docker,coreos/docker,ajaymdesai/docker,docker/docker,kencochrane/docker,mahak/docker,flavio/docker,rhatdan/docker,mkumatag/docker,resin-io/docker,Microsoft/docker,zhangjianfnst/docker,moypray/docker,thaJeztah/docker.github.io,jwhonce/docker,izarov/docker,KarthikNayak/docker,xiekeyang/docker,Tenk42/docker,nawawi/docker,dgageot/docker,gigidwan/docker,achanda/docker,KingEmet/docker,Morsicus/docker,unclejack/docker,nghiant2710/docker,Mashimiao/docker,AkihiroSuda/docker,docker/docker.github.io,gnailuy/docker,dperny/docker,bearstech/moby,cloudflare/docker,rkazak/docker,joeuo/docker.github.io,danix800/docker.github.io,gigidwan/docker,jongiddy/docker,mikedougherty/docker,stevvooe/docker,jc-m/docker,menglingwei/denverdino.github.io,catinthesky/docker,ibuildthecloud/docker,moul/docker,tkopczynski/docker,dgageot/docker,runcom/docker,liaoqingwei/docker,ailispaw/docker,OnePaaS/docker,abhinavdahiya/docker,brahmaroutu/docker,mgoelzer/docker,BenHall/docker,denverdino/docker.github.io,imkin/moby,AkihiroSuda/docker,jlebon/docker,diogomonica/docker,fcrisciani/docker,jlebon/docker,denverdino/docker.github.io,raja-sami-10p/moby,sdurrheimer/docker,Mokolea/docker,diogomonica/docker,ZJUshuaizhou/docker,abhinavdahiya/docker,rancher/docker,toli/docker,cmehay/docker-1,vdemeester/docker,shhsu/docker,x1022as/docker,yosifkit/docker,pyotr777/docker,laijs/moby,ajaymdesai/docker,medallia/docker,SvenDowideit/docker,shubheksha/docker.github.io,Morsicus/docker,YuPengZTE/docker,tonistiigi/docker,TrumanLing/docker,mikebrow/docker,anujbahuguna/docker,denverdino/denverdino.github.io,Shopify/docker,laijs/moby,tagomoris/docker,ZJUshuaizhou/docker,madhanrm/docker,xiaods/docker,srust/docker,xiaods/docker,LaynePeng/docker,yummypeng/docker,HackToday/docker,rhatdan/storage,lixiaobing1/docker,cloudflare/docker,bdwill/docker.github.io,jzwlqx/denverdino.github.io,LuisBosquez/docker.github.io,sheimi/docker,djs55/docker,KarthikNayak/docker,sdurrheimer/docker,gao-feng/docker,coreos/docker,denverdino/denverdino.github.io,nalind/docker,mgoelzer/docker,lixiaobing10051267/docker,johnstep/docker.github.io,menglingwei/denverdino.github.io,sunyuan3/docker,phiroict/docker,fsoppelsa/docker,noironetworks/docker,moypray/docker,dnephin/docker,charleszheng44/moby,alfred-landrum/docker,jameszhan/docker,ndeloof/docker,jlebon/docker,kojiromike/docker,bdwill/docker.github.io,duglin/docker,alfred-landrum/docker,shin-/docker.github.io,luxas/docker,LuisBosquez/docker.github.io,gdevillele/docker.github.io,alexisbellido/docker.github.io,sunyuan3/docker,HideoYamauchi/docker,cr7pt0gr4ph7/docker,maxamillion/docker,docker-zh/docker.github.io,paralin/docker,tpounds/docker,sheimi/docker,gdevillele/docker.github.io,mohmost12/docker,coolljt0725/docker,haveatry/docker,mathewkoshy493/docker,umerazad/docker,haveatry/docker,afein/docker,dgageot/docker,madhanrm/docker,hustcat/docker,mohmost12/docker,gao-feng/docker,allencloud/docker,ajaymdesai/docker,Mokolea/docker,anortef/docker,moxiegirl/docker,POLJM242/docker,izarov/docker,lixiaobing1/docker,twaugh/docker,runcom/docker,denverdino/denverdino.github.io,rkazak/docker,solganik/docker,jlhawn/docker,TheBigBear/docker,achanda/docker,jzwlqx/denverdino.github.io,ZJU-SEL/docker,johnstep/docker.github.io,mike1729/docker,HideoYamauchi/docker,aduermael/docker.github.io,q384566678/docker,yp-engineering/docker,jzwlqx/denverdino.github.io,thaJeztah/docker,Syntaxide/docker,msabansal/docker,cyphar/docker,afein/docker,tklauser/docker,sanscontext/docker.github.io,joaofnfernandes/docker.github.io,splunk/docker,pradipd/moby,anweiss/docker.github.io,ZJUshuaizhou/docker,darrenstahlmsft/moby,erikstmartin/docker,HackToday/docker,JimGalasyn/docker.github.io,medallia/docker,thaJeztah/docker.github.io,thaJeztah/docker,jvanz/docker,shishir-a412ed/docker,stevvooe/docker,jhorwit2/docker,danix800/docker.github.io,mathewkoshy493/docker,sallyom/docker,laijs/docker,erikh/docker,naveed-jamil-tenpearls/moby,Tenk42/docker,eskaaren/docker,cnaize/docker,justincormack/docker,bfirsh/docker,bearstech/moby,mtesselH/docker,charleszheng44/moby,Altiscale/docker,kolyshkin/docker,cpuguy83/docker,tklauser/docker,tophj-ibm/moby,kojiromike/docker,mgoelzer/docker,thaJeztah/docker.github.io,yasiramin10p/moby,upmio/docker,containers/storage,docker-zh/docker.github.io,ZJU-SEL/docker,twaugh/docker,ColinHebert/docker,sdurrheimer/docker,rillig/docker.github.io,dmcgowan/docker,mathewkoshy493/docker,sean-jc/docker,hypriot/docker,rhatdan/storage,mkumatag/docker,srust/docker,moby/moby,aduermael/docker.github.io,moby/moby,danix800/docker.github.io,upmio/docker,docker/docker,solganik/docker,dongjoon-hyun/docker,umerazad/docker,mstanleyjones/docker,Syntaxide/docker,dims/docker,tianon/docker,gjaskiewicz/moby,aduermael/docker.github.io,erikstmartin/docker,dmcgowan/docker,docker/docker,geekylucas/docker,portworx/docker,troy0820/docker.github.io,yp-engineering/docker,tkopczynski/docker,sterchelen/docker,fcrisciani/docker,mahak/docker,asbjornenge/docker,yosifkit/docker,HuKeping/docker,zhuguihua/docker,joeuo/docker.github.io,fsoppelsa/docker,jthelin/docker,x1022as/docker,TheBigBear/docker,tonistiigi/docker,cmehay/docker-1,13W/docker,jvanz/docker,troy0820/docker.github.io,michelvocks/docker,londoncalling/docker.github.io,gnailuy/docker,rillig/docker.github.io,aidanhs/docker,allencloud/docker,johnstep/moby-moby,cyli/docker,cyphar/docker,jlhawn/docker,cyli/docker,icecrime/docker,tmp6154/docker,BSWANG/denverdino.github.io,noxiouz/docker,sarnautov/moby,londoncalling/docker.github.io,erikh/docker,icaoweiwei/docker,pecameron/docker,yongtang/docker,dims/docker,mtesselH/docker,miminar/docker,izarov/docker,isubuz/docker,gjaskiewicz/moby,achanda/docker,nguyentm83/docker,mixja/docker,dccurtis/docker,twaugh/docker,brahmaroutu/docker,londoncalling/docker.github.io,joaofnfernandes/docker.github.io,mohmost12/docker,dims/docker,cmehay/docker-1,xuxinkun/docker,Syntaxide/docker,crosbymichael/docker,pramodhkp/moby,projectatomic/docker,Mashimiao/docker,gnailuy/docker,anortef/docker,toli/docker,estesp/docker,brahmaroutu/docker,dnephin/docker,Morsicus/docker,nalind/docker,yongtang/docker,vdemeester/docker,HackToday/docker,lixiaobing10051267/docker,thaJeztah/docker,scotttlin/docker,vdemeester/docker,jwhonce/docker,Altiscale/docker,HuKeping/docker,sanscontext/docker.github.io,bdwill/docker.github.io,docker/docker.github.io,jlhawn/docker,Altiscale/docker,TrumanLing/docker,gdevillele/docker.github.io,pradipd/moby,wenchma/docker,pramodhkp/moby,cnaize/docker,justincormack/docker,cpuguy83/docker,willmtemple/docker,imkin/moby,sterchelen/docker,tmp6154/docker,michelvocks/docker,qudongfang/docker,endophage/docker,djs55/docker,dsheets/moby,maxamillion/docker,thtanaka/docker,danyalKhaliq10p/moby,konstruktoid/docker-upstream,cpuguy83/docker,SvenDowideit/docker,jvanz/docker,unclejack/docker,yasiramin10p/moby,rancher/docker,phiroict/docker,asbjornenge/docker,alexisbellido/docker.github.io,dsau/docker,ffoysal/docker,prertik/docker,denverdino/denverdino.github.io,amatsus/docker,johnstep/docker.github.io,bonczj/moby-json-file-logger,portworx/docker,kerneltime/docker,liaoqingwei/docker,medallia/docker,pramodhkp/moby,Microsoft/docker,kencochrane/docker,ibuildthecloud/docker,charleswhchan/docker,anweiss/docker.github.io,zhuguihua/docker,docker/docker.github.io,Mokolea/docker,xiekeyang/docker,noxiouz/docker,moul/docker,ibuildthecloud/docker,LuisBosquez/docker.github.io,davinashreddy/docker,x1022as/docker,ffoysal/docker,dsheets/moby,errordeveloper/docker,kerneltime/docker,johnstep/docker.github.io,ckeyer/docker,splunk/docker,tagomoris/docker,BSWANG/denverdino.github.io,akira-baruah/docker,POLJM242/docker,pecameron/docker,eskaaren/docker,raja-sami-10p/moby,justincormack/docker,shubheksha/docker.github.io,mikebrow/docker,hypriot/docker,moby/moby,charleswhchan/docker,willmtemple/docker,imkin/moby,jameszhan/docker,ckeyer/docker,inatatsu/docker,miminar/docker,JimGalasyn/docker.github.io,sanjeo/docker,mstanleyjones/docker,zhuguihua/docker,jthelin/docker,thaJeztah/docker.github.io,jzwlqx/denverdino.github.io,thtanaka/docker,amatsus/docker,mtesselH/docker,sarnautov/moby,qudongfang/docker,thaJeztah/docker.github.io,fcrisciani/docker,JMesser81/docker,nghiant2710/docker,gschaetz/moby,carolfh/docker,paralin/docker,shubheksha/docker.github.io,crosbymichael/docker,ckeyer/docker,danix800/docker.github.io,duglin/docker,HideoYamauchi/docker,pradipd/moby,cpuguy83/docker,dsheets/moby,dongjoon-hyun/docker,LuisBosquez/docker.github.io,mikebrow/docker,ndeloof/docker,qudongfang/docker,runcom/docker,containers/storage,bdwill/docker.github.io,denverdino/docker.github.io,Ramzec/docker,Tenk42/docker,anortef/docker,13W/docker,BenHall/docker,jc-m/docker,catinthesky/docker,jhorwit2/docker,carolfh/docker,TrumanLing/docker,noironetworks/docker,tophj-ibm/docker,OnePaaS/docker,davinashreddy/docker,alexisbellido/docker.github.io,whuwxl/docker,moby/moby,michael-holzheu/docker,joaofnfernandes/docker.github.io,pyotr777/docker,yp-engineering/docker,tophj-ibm/docker,cr7pt0gr4ph7/docker,mtanlee/docker,geekylucas/docker,ibuildthecloud/docker,bluebreezecf/docker,nghiant2710/docker,hqhq/moby,KarthikNayak/docker,justyntemme/docker,paralin/docker,KingEmet/docker,dongjoon-hyun/docker,ibuildthecloud/docker,prertik/docker,mtanlee/docker,SvenDowideit/docker,nalind/docker,icaoweiwei/docker,nawawi/docker,fsoppelsa/docker,mikedougherty/docker,13W/docker,luxas/docker,yosifkit/docker,moypray/docker,umerazad/docker,isubuz/docker,TheBigBear/docker,djs55/docker,rremer/moby,tianon/docker,msabansal/docker,kolyshkin/moby,moul/docker,kolyshkin/moby,tklauser/docker,YuPengZTE/docker,docker-zh/docker.github.io,tkopczynski/docker,laijs/moby,mikedougherty/docker,tophj-ibm/docker,shhsu/docker,alexisbellido/docker.github.io,Shopify/docker,rremer/moby,trebonian/docker,jongiddy/docker,mike1729/docker,pyotr777/docker,kencochrane/docker,scotttlin/docker,afein/docker,LuisBosquez/docker.github.io,kolyshkin/docker,erikstmartin/docker,mahak/docker,darrenstahlmsft/docker,bluebreezecf/docker,docker-zh/docker.github.io,jecarey/docker,dmcgowan/docker