chore: fix phpstan errors

src/Controller/Booking/Create/Step3Controller.php

@@ -220,6 +220,7 @@ class Step3Controller extends AbstractController
     /**
      * Renders the step 3 form with standard template variables.
      */
+    /** @param FormInterface<mixed> $form */
     private function renderStepForm(BookingDto $bookingCreateDto, FormInterface $form): Response
     {
         $context = $this->createContextFactory->create(