Merge branch '7.2' into 7.3

* 7.2:
  use ? before nullable single type declaration
  [Twig] [Twig Reference] fix path parameter and add example in asset v…
  Update serializer.rst

Author: xabbuh

reference/twig_reference.rst

@@ -130,8 +130,10 @@ asset_version
 
 .. code-block:: twig
 
-    {{ asset_version(packageName = null) }}
+    {{ asset_version(path, packageName = null) }}
 
+``path``
+    **type**: ``string``
 ``packageName`` *(optional)*
     **type**: ``string`` | ``null`` **default**: ``null``
 

serializer.rst

@@ -1774,7 +1774,7 @@ identifier of the next nested object, instead of omitting the property::
     $child = new Person('Joe', $mother);
 
     // all callback parameters are optional (you can omit the ones you don't use)
-    $maxDepthHandler = function (object $innerObject, object $outerObject, string $attributeName, ?string $format = null, array $context = []): string {
+    $maxDepthHandler = function (object $innerObject, object $outerObject, string $attributeName, ?string $format = null, array $context = []): ?string {
         // return only the name of the next person in the tree
         return $innerObject instanceof Person ? $innerObject->getName() : null;
     };