Merge branch '6.4' into 7.2

* 6.4:
  fix EmojiTransliterator return type compatibility with PHP 8.5
  Bump Symfony version to 6.4.22
  Update VERSION for 6.4.21
  Update CONTRIBUTORS for 6.4.21
  Update CHANGELOG for 6.4.21
  Fix return type is non-nullable
  Fix overwriting an array element

Author: xabbuh

Extension/Core/Type/WeekType.php

@@ -39,7 +39,6 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
         } else {
             $yearOptions = $weekOptions = [
                 'error_bubbling' => true,
-                'empty_data' => '',
             ];
             // when the form is compound the entries of the array are ignored in favor of children data
             // so we need to handle the cascade setting here

Tests/Fixtures/TestExtension.php

@@ -34,7 +34,7 @@ public function addType(FormTypeInterface $type)
 
     public function getType($name): FormTypeInterface
     {
-        return $this->types[$name] ?? null;
+        return $this->types[$name];
     }
 
     public function hasType($name): bool