[Form] Adding @var PHPDoc to silence psalm

Author: ThomasLandauer

src/Symfony/Component/Form/Extension/Core/Type/ChoiceType.php

@@ -30,6 +30,7 @@
 use Symfony\Component\Form\ChoiceList\View\ChoiceGroupView;
 use Symfony\Component\Form\ChoiceList\View\ChoiceListView;
 use Symfony\Component\Form\ChoiceList\View\ChoiceView;
+use Symfony\Component\Form\Event\PreSubmitEvent;
 use Symfony\Component\Form\Exception\TransformationFailedException;
 use Symfony\Component\Form\Extension\Core\DataMapper\CheckboxListMapper;
 use Symfony\Component\Form\Extension\Core\DataMapper\RadioListMapper;
@@ -101,6 +102,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
             // Make sure that scalar, submitted values are converted to arrays
             // which can be submitted to the checkboxes/radio buttons
             $builder->addEventListener(FormEvents::PRE_SUBMIT, static function (FormEvent $event) use ($choiceList, $options, &$unknownValues) {
+                /** @var PreSubmitEvent $event */
                 $form = $event->getForm();
                 $data = $event->getData();