Ajax headers for dashboard/config forms

html/includes/forms/update-config-item.inc.php

@@ -11,6 +11,7 @@
  * option) any later version.  Please see LICENSE.txt at the top level of
  * the source code distribution for details.
  */
+header('Content-type: application/json');
 
 if (is_admin() === false) {
     die('ERROR: You need to be admin');