Issue #3413733: Fix Drupal 10 compatibility for getSubscribedEvents()

Closes #3413733

src/Routing/RouteSubscriber.php

@@ -45,7 +45,7 @@ class RouteSubscriber extends RouteSubscriberBase {
   /**
    * {@inheritdoc}
    */
-  public static function getSubscribedEvents() {
+  public static function getSubscribedEvents(): array {
     $events[RoutingEvents::FINISHED] = ['routeRebuildFinished', -100];
     $events[RoutingEvents::ALTER] = ['onAlterRoutes', -200];
     return $events;