[javascript mode] Support typescript's type keyword
[javascript mode] Support typescript's type keyword

Closes #4220

SidPresse/CodeMirror,crazy4chrissi/CodeMirror,jayaprabhakar/CodeMirror,kerabromsmu/CodeMirror,wingify/CodeMirror,ficristo/CodeMirror,MarcelGerber/CodeMirror,adobe/CodeMirror2,adobe/CodeMirror2,kerabromsmu/CodeMirror,thomasjm/CodeMirror,ejgallego/CodeMirror,TDaglis/CodeMirror,xeronith/CodeMirror,wingify/CodeMirror,xeronith/CodeMirror,grzegorzmazur/CodeMirror,jkaplon/CodeMirror,jkaplon/CodeMirror,dperetti/CodeMirror,xeronith/CodeMirror,wingify/CodeMirror,dperetti/CodeMirror,namin/CodeMirror,INTELOGIE/CodeMirror,SidPresse/CodeMirror,mtaran-google/CodeMirror,nightwing/CodeMirror,SidPresse/CodeMirror,codio/CodeMirror,codio/CodeMirror,schanzer/CodeMirror,nightwing/CodeMirror,MarcelGerber/CodeMirror,nightwing/CodeMirror,INTELOGIE/CodeMirror,adobe/CodeMirror2,notepadqq/CodeMirror,TDaglis/CodeMirror,jayaprabhakar/CodeMirror,sourcelair/CodeMirror,ejgallego/CodeMirror,kerabromsmu/CodeMirror,alur/CodeMirror,alur/CodeMirror,schanzer/CodeMirror,namin/CodeMirror,schanzer/CodeMirror,alur/CodeMirror,jkaplon/CodeMirror,dperetti/CodeMirror,TDaglis/CodeMirror,hackmdio/CodeMirror,mtaran-google/CodeMirror,crazy4chrissi/CodeMirror,grzegorzmazur/CodeMirror,notepadqq/CodeMirror,INTELOGIE/CodeMirror,pabloferz/CodeMirror,ficristo/CodeMirror,codio/CodeMirror,rrandom/CodeMirror,crazy4chrissi/CodeMirror,mtaran-google/CodeMirror,jayaprabhakar/CodeMirror,hackmdio/CodeMirror,rrandom/CodeMirror,ficristo/CodeMirror,sourcelair/CodeMirror,pabloferz/CodeMirror,ejgallego/CodeMirror,sourcelair/CodeMirror,grzegorzmazur/CodeMirror,namin/CodeMirror,thomasjm/CodeMirror,pabloferz/CodeMirror,thomasjm/CodeMirror,notepadqq/CodeMirror,rrandom/CodeMirror,hackmdio/CodeMirror,MarcelGerber/CodeMirror