Resolve #3238915 "Refactor if feasible"

Closes #3238915

core/modules/hal/src/Normalizer/ContentEntityNormalizer.php

@@ -66,7 +66,7 @@ public function __construct(LinkManagerInterface $link_manager, EntityTypeManage
   /**
    * {@inheritdoc}
    */
-  public function normalize($entity, $format = NULL, array $context = []) {
+  public function normalize($entity, $format = NULL, array $context = []): array|string|int|float|bool|\ArrayObject|NULL {
     $context += [
       'account' => NULL,
       'included_fields' => NULL,