Remove Handlebars support (#116)

There is a dedicated linter for Handlebars, removing this as it isn't fully supported in the first place.

Author: Arcanemagus

lib/index.js

@@ -7,7 +7,6 @@ const GRAMMAR_SCOPES = [
   'text.html.gohtml',
   'text.html.jsp',
   'text.html.mustache',
-  'text.html.handlebars',
   'text.html.ruby'
 ];