Fix bug with tools/html-grep.
Fix bug with tools/html-grep.

We were ignoring singleton tags like "input" tags in
html-grep.  This was an artifact of our tokenizer originally
being built to check indentation of templates, for which
singleton tags had been a distraction. This fix actually cleans up
the template checking logic as well, since it can now rely
on the tokenizer to classify special tags and singleton tags.
The tokenizer is more complete and more specific.

j831/zulip,rishig/zulip,Juanvulcano/zulip,showell/zulip,KingxBanana/zulip,punchagan/zulip,brockwhittaker/zulip,eeshangarg/zulip,jainayush975/zulip,reyha/zulip,tommyip/zulip,sonali0901/zulip,ahmadassaf/zulip,andersk/zulip,dattatreya303/zulip,mahim97/zulip,samatdav/zulip,peguin40/zulip,Diptanshu8/zulip,niftynei/zulip,dattatreya303/zulip,joyhchen/zulip,mahim97/zulip,vabs22/zulip,Juanvulcano/zulip,jphilipsen05/zulip,showell/zulip,kou/zulip,peguin40/zulip,rht/zulip,JPJPJPOPOP/zulip,paxapy/zulip,cosmicAsymmetry/zulip,JPJPJPOPOP/zulip,andersk/zulip,zacps/zulip,vabs22/zulip,vaidap/zulip,PhilSk/zulip,timabbott/zulip,jainayush975/zulip,JPJPJPOPOP/zulip,sonali0901/zulip,vabs22/zulip,paxapy/zulip,grave-w-grave/zulip,sonali0901/zulip,amyliu345/zulip,AZtheAsian/zulip,SmartPeople/zulip,JPJPJPOPOP/zulip,Diptanshu8/zulip,tommyip/zulip,zacps/zulip,paxapy/zulip,sharmaeklavya2/zulip,mohsenSy/zulip,synicalsyntax/zulip,eeshangarg/zulip,shubhamdhama/zulip,hackerkid/zulip,amanharitsh123/zulip,AZtheAsian/zulip,krtkmj/zulip,Galexrt/zulip,shubhamdhama/zulip,zacps/zulip,amanharitsh123/zulip,sharmaeklavya2/zulip,isht3/zulip,vaidap/zulip,jainayush975/zulip,amyliu345/zulip,krtkmj/zulip,isht3/zulip,Galexrt/zulip,kou/zulip,punchagan/zulip,mohsenSy/zulip,jrowan/zulip,blaze225/zulip,joyhchen/zulip,dhcrzf/zulip,showell/zulip,samatdav/zulip,samatdav/zulip,dhcrzf/zulip,sharmaeklavya2/zulip,calvinleenyc/zulip,KingxBanana/zulip,jackrzhang/zulip,amyliu345/zulip,ahmadassaf/zulip,andersk/zulip,dhcrzf/zulip,verma-varsha/zulip,brockwhittaker/zulip,aakash-cr7/zulip,krtkmj/zulip,rishig/zulip,jphilipsen05/zulip,jackrzhang/zulip,brainwane/zulip,andersk/zulip,joyhchen/zulip,calvinleenyc/zulip,brockwhittaker/zulip,peguin40/zulip,Galexrt/zulip,reyha/zulip,grave-w-grave/zulip,mahim97/zulip,hackerkid/zulip,umkay/zulip,blaze225/zulip,brainwane/zulip,j831/zulip,tommyip/zulip,christi3k/zulip,calvinleenyc/zulip,rht/zulip,isht3/zulip,verma-varsha/zulip,niftynei/zulip,TigorC/zulip,paxapy/zulip,jainayush975/zulip,sonali0901/zulip,jackrzhang/zulip,SmartPeople/zulip,dattatreya303/zulip,vikas-parashar/zulip,Jianchun1/zulip,amanharitsh123/zulip,ahmadassaf/zulip,zulip/zulip,susansls/zulip,verma-varsha/zulip,shubhamdhama/zulip,rht/zulip,zulip/zulip,Juanvulcano/zulip,SmartPeople/zulip,joyhchen/zulip,eeshangarg/zulip,Juanvulcano/zulip,eeshangarg/zulip,calvinleenyc/zulip,verma-varsha/zulip,brainwane/zulip,blaze225/zulip,samatdav/zulip,sonali0901/zulip,AZtheAsian/zulip,jrowan/zulip,mahim97/zulip,timabbott/zulip,Diptanshu8/zulip,jphilipsen05/zulip,vabs22/zulip,jackrzhang/zulip,Diptanshu8/zulip,mohsenSy/zulip,arpith/zulip,zulip/zulip,KingxBanana/zulip,aakash-cr7/zulip,punchagan/zulip,joyhchen/zulip,PhilSk/zulip,sharmaeklavya2/zulip,shubhamdhama/zulip,amanharitsh123/zulip,punchagan/zulip,isht3/zulip,vabs22/zulip,jackrzhang/zulip,KingxBanana/zulip,PhilSk/zulip,punchagan/zulip,synicalsyntax/zulip,tommyip/zulip,blaze225/zulip,sup95/zulip,arpith/zulip,kou/zulip,brockwhittaker/zulip,rishig/zulip,synicalsyntax/zulip,mohsenSy/zulip,dawran6/zulip,susansls/zulip,calvinleenyc/zulip,kou/zulip,SmartPeople/zulip,niftynei/zulip,sup95/zulip,Diptanshu8/zulip,niftynei/zulip,sharmaeklavya2/zulip,eeshangarg/zulip,paxapy/zulip,KingxBanana/zulip,mahim97/zulip,jainayush975/zulip,rht/zulip,Jianchun1/zulip,TigorC/zulip,eeshangarg/zulip,Galexrt/zulip,dawran6/zulip,brainwane/zulip,sup95/zulip,timabbott/zulip,kou/zulip,amyliu345/zulip,peguin40/zulip,rht/zulip,aakash-cr7/zulip,aakash-cr7/zulip,JPJPJPOPOP/zulip,AZtheAsian/zulip,ahmadassaf/zulip,zacps/zulip,Diptanshu8/zulip,rht/zulip,susansls/zulip,jphilipsen05/zulip,sharmaeklavya2/zulip,zulip/zulip,hackerkid/zulip,j831/zulip,dhcrzf/zulip,SmartPeople/zulip,tommyip/zulip,susansls/zulip,Jianchun1/zulip,isht3/zulip,susansls/zulip,mahim97/zulip,reyha/zulip,vikas-parashar/zulip,jphilipsen05/zulip,christi3k/zulip,synicalsyntax/zulip,blaze225/zulip,arpith/zulip,amanharitsh123/zulip,Galexrt/zulip,aakash-cr7/zulip,TigorC/zulip,PhilSk/zulip,showell/zulip,dhcrzf/zulip,christi3k/zulip,sup95/zulip,dawran6/zulip,samatdav/zulip,dattatreya303/zulip,Galexrt/zulip,JPJPJPOPOP/zulip,kou/zulip,aakash-cr7/zulip,jrowan/zulip,ryanbackman/zulip,krtkmj/zulip,ryanbackman/zulip,vabs22/zulip,vikas-parashar/zulip,souravbadami/zulip,AZtheAsian/zulip,cosmicAsymmetry/zulip,PhilSk/zulip,rishig/zulip,souravbadami/zulip,cosmicAsymmetry/zulip,eeshangarg/zulip,TigorC/zulip,samatdav/zulip,niftynei/zulip,grave-w-grave/zulip,timabbott/zulip,punchagan/zulip,vikas-parashar/zulip,AZtheAsian/zulip,j831/zulip,hackerkid/zulip,arpith/zulip,reyha/zulip,synicalsyntax/zulip,sup95/zulip,reyha/zulip,j831/zulip,Juanvulcano/zulip,timabbott/zulip,rishig/zulip,ryanbackman/zulip,sup95/zulip,vaidap/zulip,souravbadami/zulip,susansls/zulip,krtkmj/zulip,christi3k/zulip,sonali0901/zulip,jainayush975/zulip,ahmadassaf/zulip,mohsenSy/zulip,showell/zulip,brainwane/zulip,paxapy/zulip,vikas-parashar/zulip,cosmicAsymmetry/zulip,showell/zulip,verma-varsha/zulip,jackrzhang/zulip,jrowan/zulip,tommyip/zulip,grave-w-grave/zulip,zulip/zulip,jackrzhang/zulip,Jianchun1/zulip,synicalsyntax/zulip,timabbott/zulip,mohsenSy/zulip,isht3/zulip,vikas-parashar/zulip,amyliu345/zulip,peguin40/zulip,verma-varsha/zulip,umkay/zulip,Galexrt/zulip,arpith/zulip,Jianchun1/zulip,kou/zulip,punchagan/zulip,dhcrzf/zulip,souravbadami/zulip,zulip/zulip,timabbott/zulip,shubhamdhama/zulip,souravbadami/zulip,umkay/zulip,cosmicAsymmetry/zulip,umkay/zulip,KingxBanana/zulip,krtkmj/zulip,grave-w-grave/zulip,dawran6/zulip,PhilSk/zulip,brockwhittaker/zulip,zulip/zulip,jphilipsen05/zulip,ryanbackman/zulip,brainwane/zulip,hackerkid/zulip,vaidap/zulip,ryanbackman/zulip,rht/zulip,Jianchun1/zulip,andersk/zulip,brockwhittaker/zulip,ahmadassaf/zulip,ryanbackman/zulip,showell/zulip,dhcrzf/zulip,amanharitsh123/zulip,niftynei/zulip,andersk/zulip,umkay/zulip,rishig/zulip,shubhamdhama/zulip,peguin40/zulip,dawran6/zulip,blaze225/zulip,dattatreya303/zulip,dattatreya303/zulip,TigorC/zulip,umkay/zulip,umkay/zulip,TigorC/zulip,souravbadami/zulip,dawran6/zulip,calvinleenyc/zulip,j831/zulip,ahmadassaf/zulip,Juanvulcano/zulip,SmartPeople/zulip,zacps/zulip,zacps/zulip,synicalsyntax/zulip,amyliu345/zulip,hackerkid/zulip,christi3k/zulip,vaidap/zulip,christi3k/zulip,arpith/zulip,tommyip/zulip,andersk/zulip,brainwane/zulip,rishig/zulip,jrowan/zulip,grave-w-grave/zulip,vaidap/zulip,joyhchen/zulip,krtkmj/zulip,cosmicAsymmetry/zulip,hackerkid/zulip,jrowan/zulip,reyha/zulip,shubhamdhama/zulip