minor #17852 Update documentation for Bundle configuration (Punt13140)

This PR was merged into the 6.2 branch.

Discussion
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Update documentation for Bundle configuration

Just two import missing in bundle configuration using AbstractBundle

Commits
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08fa6d1 Import

Author: javiereguiluz

bundles/configuration.rst

@@ -334,6 +334,8 @@ add this logic to the bundle class directly::
     namespace Acme\SocialBundle;
 
     use Symfony\Component\Config\Definition\Configurator\DefinitionConfigurator;
+    use Symfony\Component\DependencyInjection\ContainerBuilder;
+    use Symfony\Component\DependencyInjection\Loader\Configurator\ContainerConfigurator;
     use Symfony\Component\HttpKernel\Bundle\AbstractBundle;
 
     class AcmeSocialBundle extends AbstractBundle