minor #20021 Update configuration.rst (DennisdeBest)

This PR was submitted for the 7.1 branch but it was merged into the 6.4 branch instead.

Discussion
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Update configuration.rst

Fix $containerConfigurator parameter name in loadExtension function

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Commits
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10abade Update configuration.rst

Author: xabbuh

bundles/configuration.rst

@@ -97,7 +97,7 @@ class, you can add all the logic related to processing the configuration in that
             // the "$config" variable is already merged and processed so you can
             // use it directly to configure the service container (when defining an
             // extension class, you also have to do this merging and processing)
-            $containerConfigurator->services()
+            $container->services()
                 ->get('acme_social.twitter_client')
                 ->arg(0, $config['twitter']['client_id'])
                 ->arg(1, $config['twitter']['client_secret'])