Merge branch '4.3' into 4.4

* 4.3:
  Useless code in an example
  Update Doc : Symfony 4.3 - Swift Mailer
  Fixed the link to the ErrorRenderer component page

Author: OskarStark

components/yaml.rst

@@ -289,8 +289,6 @@ Similarly you can use ``DUMP_EXCEPTION_ON_INVALID_TYPE`` when dumping::
     $data = new \stdClass(); // by default objects are invalid.
     Yaml::dump($data, 2, 4, Yaml::DUMP_EXCEPTION_ON_INVALID_TYPE); // throws an exception
 
-    echo $yaml; // { foo: bar }
-
 Date Handling
 ~~~~~~~~~~~~~