minor symfony#8345 Update storage.rst (atailouloute)

This PR was submitted for the 3.2 branch but it was merged into the 2.7 branch instead (closes symfony#8345).

Discussion
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Update storage.rst

Commits
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328cb43 Update storage.rst

Author: xabbuh

profiler/storage.rst

@@ -50,7 +50,7 @@ uses MySQL as the storage for the profiler with a lifetime of one hour:
         // ...
         $container->loadFromExtension('framework', array(
             'profiler' => array(
-                'dsn'      => 'mysql:host=localhost;dbname=%database_name%',
+                'dsn' => 'mysql:host=localhost;dbname=%database_name%',
                 'username' => '%database_user',
                 'password' => '%database_password%',
                 'lifetime' => 3600,