Fix docblock for Model::getEventDispatcher() (#52602)

* Update Model.php

* Update HasEvents.php

* Update HasEvents.php

* Update Model.php

---------

Co-authored-by: Taylor Otwell <[email protected]>

Author: inmula

src/Illuminate/Database/Eloquent/Concerns/HasEvents.php

@@ -399,7 +399,7 @@ public function dispatchesEvents()
     /**
      * Get the event dispatcher instance.
      *
-     * @return \Illuminate\Contracts\Events\Dispatcher
+     * @return \Illuminate\Contracts\Events\Dispatcher|null
      */
     public static function getEventDispatcher()
     {

src/Illuminate/Database/Eloquent/Model.php

@@ -134,7 +134,7 @@ abstract class Model implements Arrayable, ArrayAccess, CanBeEscapedWhenCastToSt
     /**
      * The event dispatcher instance.
      *
-     * @var \Illuminate\Contracts\Events\Dispatcher
+     * @var \Illuminate\Contracts\Events\Dispatcher|null
      */
     protected static $dispatcher;