Use $(fn)

This is the recommended way in jQuery 3.x.

Signed-off-by: XhmikosR <xhmikosr@gmail.com>

scripts/pi-hole/js/groups-clients.js

@@ -57,7 +57,7 @@ function getGroups() {
   );
 }
 
-$(document).ready(function () {
+$(function () {
   $("#btnAdd").on("click", addClient);
 
   reloadClientSuggestions();