Highlight translation comments in QML.

Author: seanwu1105

syntaxes/qml.tmLanguage.json

@@ -260,6 +260,20 @@
     },
     "comment": {
       "patterns": [
+        {
+          "begin": "(\\/\\/:)",
+          "beginCaptures": {
+            "1": {
+              "name": "storage.type.class.qml.tr"
+            }
+          },
+          "end": "$",
+          "patterns": [
+            {
+              "include": "#comment-contents"
+            }
+          ]
+        },
         {
           "begin": "(\\/\\/[~|=])\\s*([A-Za-z_$][\\w$.\\[\\]]*)",
           "beginCaptures": {