minor #6149 Reference to session + Corrected sample code char (sfdumi)

This PR was submitted for the 3.0 branch but it was merged into the 2.8 branch instead (closes #6149).

Discussion
----------

Reference to session + Corrected sample code char

Corrected reference to user with reference to session + Removed extra parenthesis from code sample.

Commits
-------

fc32f7f Reference to session + Corrected sample code char

book/controller.rst

@@ -605,7 +605,7 @@ from any controller::
         $filters = $session->get('filters', array());
     }
 
-These attributes will remain on the user for the remainder of that user's
+These attributes will remain in the session for the remainder of that user's
 session.
 
 .. index::
@@ -821,7 +821,7 @@ method to check the CSRF token::
     }
 
     // isCsrfTokenValid() is equivalent to:
-    // $this->get('security.csrf.token_manager')->isTokenValid()
+    // $this->get('security.csrf.token_manager')->isTokenValid(
     //     new \Symfony\Component\Security\Csrf\CsrfToken\CsrfToken('token_id', $token)
     // );