[haxe mode] Add comment styles

Author: marijnh

mode/haxe/haxe.js

@@ -422,7 +422,10 @@ CodeMirror.defineMode("haxe", function(config, parserConfig) {
       else return lexical.indented + (closing ? 0 : indentUnit);
     },
 
-    electricChars: "{}"
+    electricChars: "{}",
+    blockCommentStart: "/*",
+    blockCommentEnd: "*/",
+    lineComment: "//"
   };
 });