Add mapping for stylus mode in LanguageManager, fixes #13378

src/language/LanguageManager.js

@@ -1161,6 +1161,10 @@ define(function (require, exports, module) {
  var scss = getLanguage("scss");
  scss._setLanguageForMode("css", scss);
 
+ // Map stylus mode to the stylus Brackets language, fixes #13378
+ var stylus = getLanguage("stylus");
+ _setLanguageForMode("stylus", stylus);
+
  // The fallback language for unknown modes and file extensions
  _fallbackLanguage = getLanguage("unknown");