minor #13846 Update TypeHint Serializer.rst (zairigimad)

This PR was merged into the 5.0 branch.

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Update TypeHint Serializer.rst

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d18a895 Update TypeHint Serializer.rst

Author: javiereguiluz

components/serializer.rst

@@ -463,12 +463,12 @@ A custom name converter can handle such cases::
 
     class OrgPrefixNameConverter implements NameConverterInterface
     {
-        public function normalize($propertyName)
+        public function normalize(string $propertyName)
         {
             return 'org_'.$propertyName;
         }
 
-        public function denormalize($propertyName)
+        public function denormalize(string $propertyName)
         {
             // removes 'org_' prefix
             return 'org_' === substr($propertyName, 0, 4) ? substr($propertyName, 4) : $propertyName;