Nav menus: Adjust redundant titles in accessibility helpers.

Merge of [33540] to the 4.2 branch.
Built from https://develop.svn.wordpress.org/branches/4.2@33541


git-svn-id: http://core.svn.wordpress.org/branches/4.2@33508 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/nav-menu.js

@@ -492,7 +492,7 @@ var wpNavMenu;
 				title = menus.subMenuFocus.replace( '%1$s', itemName ).replace( '%2$d', itemPosition ).replace( '%3$s', parentItemName );
 			}
 
-			$this.prop('title', title).html( title );
+			$this.prop('title', title).text( title );
 
 			// Mark this item's accessibility as refreshed
 			$this.data( 'needs_accessibility_refresh', false );