minor #10218 Update service_container.rst (ismail1432)

This PR was submitted for the 4.1 branch but it was merged into the 3.4 branch instead (closes #10218).

Discussion
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Update service_container.rst

there was 2 `/` instead 1, I don't know if it's intentional

Commits
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7160baf Update service_container.rst

Author: xabbuh

service_container.rst

@@ -841,7 +841,7 @@ But, with ``autoconfigure: true``, you don't need the tag. In fact, if you're us
 the :ref:`Symfony Standard Edition services.yml config <service-container-services-load-example>`,
 you don't need to do *anything*: the service will be automatically loaded. Then,
 ``autoconfigure`` will add the ``twig.extension`` tag *for* you, because your class
-implements ``Twig\\Extension\\ExtensionInterface``. And thanks to ``autowire``, you can even add
+implements ``Twig\Extension\ExtensionInterface``. And thanks to ``autowire``, you can even add
 constructor arguments without any configuration.
 
 Of course, you can still :ref:`manually configure the service <services-manually-wire-args>`