Update tags.rst

Author: danut007ro

service_container/tags.rst

@@ -70,19 +70,24 @@ then some tags are automatically applied for you. That's true for the ``twig.ext
 tag: the container sees that your class extends ``Twig_Extension`` (or more accurately,
 that it implements ``Twig_ExtensionInterface``) and adds the tag for you.
 
-In order to have a tag automatically applied to all your services that implement an interface,
-you should create an extension following the steps described in :doc:`/bundles/extension`,
-then in the ``load()`` method call ``registerForAutoconfiguration()`` and apply your tag::
-    
-    // src/AppBundle/DependencyInjection/AppExtension.php
+.. tip::
 
-    // ...
-    public function load(array $configs, ContainerBuilder $container)
-    {
-        $container->registerForAutoconfiguration(CustomInterface::class)
-            ->addTag('app.custom_tag')
-        ;
-    }
+    To apply a tag to all your autoconfigured services extending a class or an
+    interface, call ``ContainerBuilder::registerForAutoconfiguration()`` in an
+    :doc:`extension </bundles/extension>` or from your kernel::
+
+        // app/AppKernel.php
+        class AppKernel extends Kernel
+        {
+            // ...
+
+            protected function build(ContainerBuilder $container)
+            {
+                $container->registerForAutoconfiguration(CustomInterface::class)
+                    ->addTag('app.custom_tag')
+                ;
+            }
+        }
 
 Creating custom Tags
 --------------------