Merge branch '5.1'

* 5.1:
  User service() instead of ref()
  Missed cleanup in fluent migration

Author: javiereguiluz

cache.rst

@@ -564,9 +564,6 @@ to enable this feature. This could be added by using the following configuration
     .. code-block:: php
 
         // config/packages/cache.php
-        use Symfony\Component\Cache\Adapter\ChainAdapter;
-        use Symfony\Component\DependencyInjection\Reference;
-
         $container->loadFromExtension('framework', [
             'cache' => [
                 'pools' => [

reference/configuration/swiftmailer.rst

@@ -381,7 +381,6 @@ alternatives based on the :ref:`service binding <services-binding>` feature:
         // config/services.php
         use App\Some\Service;
         use Psr\Log\LoggerInterface;
-        use Symfony\Component\DependencyInjection\Reference;
 
 
         $container->register(Service::class)

service_container.rst

@@ -483,7 +483,7 @@ all their types (string, boolean, array, binary and PHP constant parameters).
 However, there is another type of parameter related to services. In YAML config,
 any string which starts with ``@`` is considered as the ID of a service, instead
 of a regular string. In XML config, use the ``type="service"`` type for the
-parameter and in PHP config use the ``Reference`` class:
+parameter and in PHP config use the ``service()`` function:
 
 .. configuration-block::