improve comment

Author: Narretz

src/ng/directive/ngRef.js

@@ -244,7 +244,7 @@ var ngRefMinErr = minErr('ngRef');
 
 var ngRefDirective = ['$parse', function($parse) {
   return {
-    priority: -1, // Needed for compatibility with transclusion
+    priority: -1, // Needed for compatibility with element transclusion on the same element
     restrict: 'A',
     compile: function(tElement, tAttrs) {
       // Get the expected controller name, converts <data-some-thing> into "someThing"