Merge branch '4.4' into 5.0

* 4.4:
  Update configuration.rst

Author: javiereguiluz

configuration.rst

@@ -829,7 +829,7 @@ part of Symfony individually by following the guides. Check out:
 * :doc:`/doctrine`
 * :doc:`/service_container`
 * :doc:`/security`
-* :doc:`/email`
+* :doc:`/mailer`
 * :doc:`/logging`
 
 And all the other topics related to configuration: