Move zsh completion logic to new subcommand: diff
Move zsh completion logic to new subcommand: diff

Signed-off-by: Steve Durrheimer <a2c1a055e5b399822be341b4e663de3cd05cf8f7@gmail.com>

lixiaobing10051267/docker,dgageot/docker,coreos/docker,maxamillion/docker,ColinHebert/docker,michael-holzheu/docker,x1022as/docker,dmcgowan/docker,dims/docker,dgageot/docker,docker/docker,bonczj/moby-json-file-logger,lixiaobing1/docker,gnailuy/docker,catinthesky/docker,thtanaka/docker,nawawi/docker,yasiramin10p/moby,sarnautov/moby,konstruktoid/docker-1,tianon/docker,konstruktoid/docker-upstream,q384566678/docker,mkumatag/docker,jimjag/docker,laijs/moby,xuxinkun/docker,kolyshkin/moby,tmp6154/docker,shhsu/docker,sdurrheimer/docker,miminar/docker,noironetworks/docker,rancher/docker,dccurtis/docker,JMesser81/docker,tklauser/docker,shhsu/docker,thtanaka/docker,michael-holzheu/docker,darrenstahlmsft/moby,harche/docker,ibuildthecloud/docker,estesp/docker,sdurrheimer/docker,Ramzec/docker,stevvooe/docker,allencloud/docker,sarnautov/moby,kolyshkin/moby,prertik/docker,coolljt0725/docker,moypray/docker,jameszhan/docker,PatrickLang/moby,q384566678/docker,madhanrm/docker,darrenstahlmsft/docker,trebonian/docker,thaJeztah/docker,POLJM242/docker,PatrickLang/moby,haveatry/docker,kojiromike/docker,bearstech/moby,kencochrane/docker,ndeloof/docker,djs55/docker,SvenDowideit/docker,srust/docker,scotttlin/docker,dccurtis/docker,bearstech/moby,jthelin/docker,scotttlin/docker,dmcgowan/docker,duglin/docker,raja-sami-10p/moby,dperny/docker,kojiromike/docker,pradipd/moby,alfred-landrum/docker,mtrmac/docker,mahak/docker,liaoqingwei/docker,alfred-landrum/docker,mtrmac/docker,Ramzec/docker,rancher/docker,darrenstahlmsft/moby,shishir-a412ed/docker,docker/docker,shhsu/docker,ripcurld0/moby,yasiramin10p/moby,gnailuy/docker,tonistiigi/docker,flavio/docker,erikh/docker,hqhq/moby,gnailuy/docker,jvanz/docker,allencloud/docker,mahak/docker,cpuguy83/docker,whuwxl/docker,jlhawn/docker,tophj-ibm/docker,mike1729/docker,mstanleyjones/docker,tmp6154/docker,johnstep/moby-moby,SvenDowideit/docker,gschaetz/moby,darrenstahlmsft/moby,fcrisciani/docker,whuwxl/docker,mkumatag/docker,justincormack/docker,moypray/docker,tophj-ibm/moby,moul/docker,prertik/docker,moypray/docker,jlhawn/docker,darrenstahlmsft/docker,miminar/docker,fcrisciani/docker,danyalKhaliq10p/moby,xuxinkun/docker,YuPengZTE/docker,qudongfang/docker,danyalKhaliq10p/moby,flavio/docker,mixja/docker,thtanaka/docker,coreos/docker,POLJM242/docker,charleszheng44/moby,yosifkit/docker,ndeloof/docker,kolyshkin/moby,kencochrane/docker,amatsus/docker,jvanz/docker,kolyshkin/docker,sterchelen/docker,naveed-jamil-tenpearls/moby,dsheets/moby,mike1729/docker,imkin/moby,Mokolea/docker,mixja/docker,ibuildthecloud/docker,nalind/docker,pramodhkp/moby,dccurtis/docker,stevvooe/docker,sdurrheimer/docker,erikh/docker,estesp/docker,mtesselH/docker,resin-io/docker,ibuildthecloud/docker,ibuildthecloud/docker,Ramzec/docker,sterchelen/docker,yosifkit/docker,rremer/moby,docker/docker,jimjag/docker,resin-io/docker,coolljt0725/docker,rhatdan/docker,charleszheng44/moby,KarthikNayak/docker,maxamillion/docker,thaJeztah/docker,KingEmet/docker,tonistiigi/docker,jwhonce/docker,dgageot/docker,q384566678/docker,imkin/moby,unclejack/docker,dmcgowan/docker,x1022as/docker,ffoysal/docker,erikstmartin/docker,dperny/docker,ndeloof/docker,ColinHebert/docker,kolyshkin/docker,yasiramin10p/moby,srust/docker,vdemeester/docker,jameszhan/docker,tklauser/docker,djs55/docker,trebonian/docker,tianon/docker,moby/moby,gjaskiewicz/moby,justincormack/docker,konstruktoid/docker-upstream,mikebrow/docker,noironetworks/docker,laijs/docker,tophj-ibm/docker,mahak/docker,catinthesky/docker,allencloud/docker,whuwxl/docker,mike1729/docker,dsheets/moby,vdemeester/docker,flavio/docker,lixiaobing1/docker,tophj-ibm/moby,sarnautov/moby,tophj-ibm/docker,bearstech/moby,coolljt0725/docker,estesp/docker,pramodhkp/moby,jimjag/docker,SvenDowideit/docker,fcrisciani/docker,paralin/docker,xuxinkun/docker,Syntaxide/docker,HideoYamauchi/docker,prertik/docker,mikebrow/docker,Mokolea/docker,Syntaxide/docker,PatrickLang/moby,konstruktoid/docker-upstream,jimjag/docker,lixiaobing10051267/docker,akira-baruah/docker,mikedougherty/docker,yongtang/docker,YuPengZTE/docker,johnstep/moby-moby,laijs/moby,JMesser81/docker,ffoysal/docker,mahak/docker,haveatry/docker,nawawi/docker,yummypeng/docker,rremer/moby,dsheets/moby,nalind/docker,lixiaobing1/docker,ffoysal/docker,crosbymichael/docker,nalind/docker,mstanleyjones/docker,sterchelen/docker,erikh/docker,yongtang/docker,tklauser/docker,mixja/docker,mikedougherty/docker,ripcurld0/moby,trebonian/docker,srust/docker,amatsus/docker,harche/docker,ColinHebert/docker,naveed-jamil-tenpearls/moby,gjaskiewicz/moby,moul/docker,cyphar/docker,imkin/moby,lixiaobing10051267/docker,jwhonce/docker,x1022as/docker,ibuildthecloud/docker,diogomonica/docker,hqhq/moby,justincormack/docker,crosbymichael/docker,Mokolea/docker,bearstech/moby,yummypeng/docker,coreos/docker,mikedougherty/docker,laijs/docker,gnailuy/docker,cyphar/docker,qudongfang/docker,stevvooe/docker,kencochrane/docker,rancher/docker,cpuguy83/docker,jlhawn/docker,nalind/docker,flavio/docker,shishir-a412ed/docker,danyalKhaliq10p/moby,nawawi/docker,YuPengZTE/docker,msabansal/docker,moul/docker,Ramzec/docker,djs55/docker,konstruktoid/docker-1,yongtang/docker,AkihiroSuda/docker,Mokolea/docker,miminar/docker,gschaetz/moby,thaJeztah/docker,KingEmet/docker,tmp6154/docker,pradipd/moby,erikstmartin/docker,yosifkit/docker,paralin/docker,akira-baruah/docker,thaJeztah/docker,Syntaxide/docker,paralin/docker,cpuguy83/docker,trebonian/docker,yosifkit/docker,jvanz/docker,alfred-landrum/docker,jameszhan/docker,KarthikNayak/docker,vdemeester/docker,qudongfang/docker,HideoYamauchi/docker,rhatdan/docker,KingEmet/docker,konstruktoid/docker-1,rremer/moby,laijs/moby,johnstep/moby-moby,duglin/docker,mikebrow/docker,msabansal/docker,moul/docker,duglin/docker,tonistiigi/docker,dims/docker,charleszheng44/moby,hqhq/moby,nawawi/docker,moby/moby,tophj-ibm/moby,mstanleyjones/docker,AkihiroSuda/docker,laijs/docker,harche/docker,KarthikNayak/docker,diogomonica/docker,unclejack/docker,dims/docker,madhanrm/docker,moby/moby,mkumatag/docker,haveatry/docker,konstruktoid/docker-upstream,HideoYamauchi/docker,mtesselH/docker,catinthesky/docker,liaoqingwei/docker,diogomonica/docker,paralin/docker,pradipd/moby,darrenstahlmsft/docker,ripcurld0/moby,erikstmartin/docker,scotttlin/docker,mtesselH/docker,naveed-jamil-tenpearls/moby,AkihiroSuda/docker,rhatdan/docker,jthelin/docker,bonczj/moby-json-file-logger,mtrmac/docker,unclejack/docker,gschaetz/moby,resin-io/docker,raja-sami-10p/moby,pramodhkp/moby,noironetworks/docker,michael-holzheu/docker,raja-sami-10p/moby,AkihiroSuda/docker,kojiromike/docker,bonczj/moby-json-file-logger,msabansal/docker,dperny/docker,cyphar/docker,jwhonce/docker,liaoqingwei/docker,gjaskiewicz/moby,yummypeng/docker,shishir-a412ed/docker,maxamillion/docker,madhanrm/docker,crosbymichael/docker,JMesser81/docker,cpuguy83/docker,moby/moby,amatsus/docker