[TOOLS] Continue raising PHPStan level to 6

components/Notification/Entity/Notification.php

@@ -117,7 +117,7 @@ class Notification extends Entity
     /**
      * Pull the complete list of known activity context notifications for this activity.
      *
-     * @return array of integer actor ids (also group profiles)
+     * @return int[] actor ids (also group profiles)
      */
     public static function getNotificationTargetIdsByActivity(int|Activity $activity_id): array
     {
@@ -129,11 +129,17 @@ class Notification extends Entity
         return $targets;
     }
 
+    /**
+     * @return int[]
+     */
     public function getNotificationTargetsByActivity(int|Activity $activity_id): array
     {
         return DB::findBy(Actor::class, ['id' => $this->getNotificationTargetIdsByActivity($activity_id)]);
     }
 
+    /**
+     * @return int[]
+     */
     public static function getAllActivitiesTargetedAtActor(Actor $actor): array
     {
         return DB::dql(<<<'EOF'