Move 'use strict' to file level

Change-Id: I1f0dae4aa168e77c112bcd3688c98b84e4ce5f36
diff --git a/dev/js/src/match/treeitem.js b/dev/js/src/match/treeitem.js
index 422f3d7..0d36724 100644
--- a/dev/js/src/match/treeitem.js
+++ b/dev/js/src/match/treeitem.js
@@ -1,5 +1,6 @@
+"use strict";
+
 define(['menu/item'], function (itemClass) {
-  "use strict";
 
   /**
    * Menu item for tree view choice.