minor #5161 Use correct Session namespace (JhonnyL)

This PR was merged into the 2.3 branch.

Discussion
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Use correct Session namespace

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets |

Commits
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7555942 Use correct Session namespace

Author: wouterj

book/internals.rst

@@ -40,8 +40,8 @@ variables:
 * The :class:`Symfony\\Component\\HttpFoundation\\Response` class abstracts
   some PHP functions like ``header()``, ``setcookie()``, and ``echo``;
 
-* The :class:`Symfony\\Component\\HttpFoundation\\Session` class and
-  :class:`Symfony\\Component\\HttpFoundation\\SessionStorage\\SessionStorageInterface`
+* The :class:`Symfony\\Component\\HttpFoundation\\Session\\Session` class and
+  :class:`Symfony\\Component\\HttpFoundation\\Session\\Storage\\SessionStorageInterface`
   interface abstract session management ``session_*()`` functions.
 
 .. note::