[jquery] Add ajaxSettings property. (#20433)

types/jquery/index.d.ts

@@ -41,6 +41,11 @@ type _Event = Event;
 type _Promise<T> = Promise<T>;
 
 interface JQueryStatic<TElement extends Node = HTMLElement> {
+    /**
+     * @see {@link http://api.jquery.com/jquery.ajax/#jQuery-ajax1}
+     * @deprecated Use jQuery.ajaxSetup(options)
+     */
+    ajaxSettings: JQuery.AjaxSettings;
     /**
      * A factory function that returns a chainable utility object with methods to register multiple
      * callbacks into callback queues, invoke callback queues, and relay the success or failure state of

types/jquery/jquery-tests.ts

@@ -62,6 +62,11 @@ function JQueryStatic() {
         $();
     }
 
+    function ajaxSettings() {
+        // $ExpectType JQuery.AjaxSettings
+        $.ajaxSettings;
+    }
+
     function Event() {
         // $ExpectType EventStatic<HTMLElement>
         $.Event;