chore: fix phpstan errors

src/Service/BookingEditSubmitGuard.php

@@ -171,6 +171,10 @@ class BookingEditSubmitGuard
         return $changed;
     }
 
+    /**
+     * @param list<Service> $left
+     * @param list<Service> $right
+     */
     private function areServiceListsEqual(array $left, array $right): bool
     {
         return $this->normalizeServiceIds($left) === $this->normalizeServiceIds($right);