minor #12421 Update dependency_injection.rst (AleksejJur)

This PR was merged into the 4.3 branch.

Discussion
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Update dependency_injection.rst

In previous chapter we changed our controller logic to return string, also we used ExceptionListener, if we won't register them after we move logic into Framework class we will get fatal

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Commits
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4f72d1e Update dependency_injection.rst

Author: javiereguiluz

create_framework/dependency_injection.rst

@@ -27,8 +27,12 @@ to it::
             $argumentResolver = new HttpKernel\Controller\ArgumentResolver();
 
             $dispatcher = new EventDispatcher();
+            $dispatcher->addSubscriber(new HttpKernel\EventListener\ExceptionListener(
+                'Calendar\Controller\ErrorController::exception'
+            ));
             $dispatcher->addSubscriber(new HttpKernel\EventListener\RouterListener($matcher, $requestStack));
             $dispatcher->addSubscriber(new HttpKernel\EventListener\ResponseListener('UTF-8'));
+            $dispatcher->addSubscriber(new StringResponseListener());
 
             parent::__construct($dispatcher, $controllerResolver, $requestStack, $argumentResolver);
         }