chore: fix phpstan errors

src/BusProNet/Form/CountryType.php

@@ -10,6 +10,7 @@ use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Symfony\Component\OptionsResolver\Options;
 use Symfony\Component\OptionsResolver\OptionsResolver;
 
+/** @extends AbstractType<string> */
 class CountryType extends AbstractType
 {
     public function __construct(private readonly CountryDataProvider $countries)