Feature: Add Surface language and integrate with Elixir (#1645)

* Add initial surface highlights & injections

* Additional surface highlights

* Filetype detection, fix injections

* Fix Elixir function highlight when left is an identifier

* Add surface parser

* Fix comment highlights

* Surface folds, indents, better highlights

* Highlight surface components & directives

* Restore comments Elixir injections

queries/elixir/highlights.scm

@@ -78,6 +78,10 @@
  remote: [(atom) (module)] @type
  function: (function_identifier) @method)
 
+(dot_call
+ remote: (identifier) @variable
+ function: (function_identifier) @method)
+
 "fn" @keyword.function
 
 ; def, defp, defguard, ... everything that starts with def

queries/elixir/injections.scm

@@ -8,3 +8,8 @@
    (sigil_start) @_start
    (sigil_content) @regex)
  (#match? @_start "~(r|R)[/</\\\"[({|]"))
+
+((sigil
+   (sigil_start) @_start
+   (sigil_content) @surface)
+ (#eq? @_start "~F\"\"\""))