minor #11838 Refactor documentation - Do not add annotation configuration if you are using Symfony Flex (idetox, elescot)

This PR was merged into the 4.3 branch.

Discussion
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Refactor documentation - Do not add annotation configuration if you are using Symfony Flex

Do not add annotation routing configuration if your project uses Symfony Flex since the recipe already added the annotations.yaml file with the config inside.

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Commits
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8557b34 Removing space before colon
5190b5e Refactor documentation assuming we use Symfony Flex
e1521a0 Update controllers.rst

Author: javiereguiluz

best_practices/controllers.rst

@@ -47,14 +47,19 @@ this suffix is neither required nor recommended, so you can safely remove it.
 Routing Configuration
 ---------------------
 
-To load routes defined as annotations in your controllers, add the following
-configuration to the main routing configuration file:
+To load routes defined as annotations in your controllers, run the following command:
+
+.. code-block:: terminal
+
+    $ composer require doctrine/annotations
+
+Thanks to the :doc:`Flex recipe</setup/flex>`, a ``config/routes/annotations.yaml`` file will be created:
 
 .. code-block:: yaml
 
-    # config/routes.yaml
+    # config/routes/annotations.yaml
     controllers:
-        resource: '../src/Controller/'
+        resource: '../../src/Controller/'
         type:     annotation
 
 This configuration will load annotations from any controller stored inside the