minor symfony#9702 Fix show code without new line (liviubalan)

This PR was submitted for the 3.3 branch but it was merged into the 3.4 branch instead (closes symfony#9702).

Discussion
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Fix show code without new line

Show "composer require symfony/swiftmailer-bundle" without new line

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Commits
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c28d882 Fix show code without new line

Author: javiereguiluz

setup/flex.rst

@@ -74,12 +74,12 @@ SwiftmailerBundle:
     }
 
 The ``aliases`` option allows Flex to install packages using short and easy to
-remember names (``composer require mailer`` vs ``composer require
-symfony/swiftmailer-bundle``). The ``bundles`` option tells Flex in which
-environments this bundle should be enabled automatically (``all`` in this
-case). The ``env`` option makes Flex to add new environment variables to the
-application. Finally, the ``copy-from-recipe`` option allows the recipe to copy
-files and directories into your application.
+remember names (``composer require mailer`` vs
+``composer require symfony/swiftmailer-bundle``). The ``bundles`` option tells
+Flex in which environments this bundle should be enabled automatically (``all``
+in this case). The ``env`` option makes Flex to add new environment variables to
+the application. Finally, the ``copy-from-recipe`` option allows the recipe to
+copy files and directories into your application.
 
 The instructions defined in this ``manifest.json`` file are also used by
 Symfony Flex when uninstalling dependencies (e.g. ``composer remove mailer``)