Fix Dispatcher::until return type (#47585)

Author: Neol3108

src/Illuminate/Contracts/Events/Dispatcher.php

@@ -34,7 +34,7 @@ public function subscribe($subscriber);
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @return array|null
+     * @return mixed
      */
     public function until($event, $payload = []);
 

src/Illuminate/Events/Dispatcher.php

@@ -215,7 +215,7 @@ protected function resolveSubscriber($subscriber)
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @return array|null
+     * @return mixed
      */
     public function until($event, $payload = [])
     {

src/Illuminate/Events/NullDispatcher.php

@@ -57,7 +57,7 @@ public function push($event, $payload = [])
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @return array|null
+     * @return mixed
      */
     public function until($event, $payload = [])
     {

src/Illuminate/Support/Testing/Fakes/EventFake.php

@@ -377,7 +377,7 @@ public function forgetPushed()
      *
      * @param  string|object  $event
      * @param  mixed  $payload
-     * @return array|null
+     * @return mixed
      */
     public function until($event, $payload = [])
     {