Move 'use strict' to file level

Change-Id: I1f0dae4aa168e77c112bcd3688c98b84e4ce5f36
diff --git a/dev/js/src/menu.js b/dev/js/src/menu.js
index ecce23b..9d3c44e 100644
--- a/dev/js/src/menu.js
+++ b/dev/js/src/menu.js
@@ -14,6 +14,8 @@
  * TODO: Add static header (for title, sortation fields, but also for menu points like "fragments" and "history".
  * TODO: Support space separated list of prefixes so "co no" will highlight "common noun"
  */
+
+"use strict";
 define([
   'menu/item',
   'menu/prefix',
@@ -25,8 +27,6 @@
              defaultLengthFieldClass,
              sliderClass) {
 
-  "use strict";
-
   // Default maximum number of menu items
   const menuLimit = 8;