Rework the handlebars highlighter
Rework the handlebars highlighter

- Removes -recurse from handlebars comments. Handlebars parsers (janl/mustache.js, ember-cli/ember-cli-htmlbars), do not treat comments as recursive, so don't highlight them as so.
- Creates shared/hbs-file highligher group. This represents a handlebars file, which is html that happens to contain some handlebars tags.
- Augments the shared/html highlighter when needed. Because handlebars lives inside of html, we need to add the highlighter inside of it. Since there's no way to scope modifications of a shared highlighter to a window, here I'm modifying/unmodifying the shared/html highlighter whenever the user attaches/detaches a filetype of "hbs" to/from the window.
- Matches namespaced helpers as well. In htmlbars, helpers (components) can have '/'s in them, so make sure to continue highlighting through those. Also removes unused capturing groups.
- Allows for de-indenting when closing a block expression
- Brings in html highlighter hooks
- Improves indent matching on close of yielded blocks. Previous version just flat out didn't work.

casimir/kakoune,Somasis/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,danr/kakoune,Somasis/kakoune,casimir/kakoune,jjthrash/kakoune,jjthrash/kakoune,mawww/kakoune,lenormf/kakoune,casimir/kakoune,occivink/kakoune,mawww/kakoune,lenormf/kakoune,mawww/kakoune,Somasis/kakoune,occivink/kakoune,danr/kakoune,Somasis/kakoune,lenormf/kakoune,occivink/kakoune,alexherbo2/kakoune,occivink/kakoune,jjthrash/kakoune,lenormf/kakoune,alexherbo2/kakoune,mawww/kakoune,jkonecny12/kakoune,jkonecny12/kakoune,jkonecny12/kakoune,alexherbo2/kakoune,danr/kakoune,jjthrash/kakoune,danr/kakoune,casimir/kakoune