Merge branch '4.4' into 5.0

* 4.4:
  Update serializer.rst

Author: javiereguiluz

components/serializer.rst

@@ -126,7 +126,9 @@ exists in your project::
 Now, if you want to serialize this object into JSON, you only need to
 use the Serializer service created before::
 
-    $person = new App\Model\Person();
+    use App\Model\Person;
+
+    $person = new Person();
     $person->setName('foo');
     $person->setAge(99);
     $person->setSportsperson(false);