minor #5816 Merge branches (nicolas-grekas, snoek09, WouterJ, xabbuh)

This PR was merged into the 2.7 branch.

Discussion
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Merge branches

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.7+
| Fixed tickets |

Merges some commits that have been done in the `2.6` branch after we stopped support for that version.

Commits
-------

ab19cfb fix code block syntax
0ed7d99 Merge remote-tracking branch 'upstream/2.6' into merge-branches
149576e feature #5310 Fix missing note about debug.dump_destination (nicolas-grekas)
f67c353 [#5572] Fix syntax
85dc294 feature #5572 4668 document isCsrfTokenValid (snoek09)
11383f8 4668 document isCsrfTokenValid
dae2811 Fix missing note about debug.dump_destination

book/controller.rst

@@ -440,7 +440,7 @@ If you want to redirect the user to another page, use the ``redirectToRoute()``
     }
 
 .. versionadded:: 2.6
-    The ``redirectToRoute()`` method was added in Symfony 2.6. Previously (and still now), you
+    The ``redirectToRoute()`` method was introduced in Symfony 2.6. Previously (and still now), you
     could use ``redirect()`` and ``generateUrl()`` together for this (see the example above).
 
 Or, if you want to redirect externally, just use ``redirect()`` and pass it the URL::
@@ -811,6 +811,29 @@ Just like when creating a controller for a route, the order of the arguments of
 order of the arguments, Symfony will still pass the correct value to each
 variable.
 
+Validating a CSRF Token
+-----------------------
+
+Sometimes, you want to use CSRF protection in an action where you don't want to
+use the Symfony Form component. If, for example, you're doing a DELETE action,
+you can use the :method:`Symfony\\Bundle\\FrameworkBundle\\Controller\\Controller::isCsrfTokenValid`
+method to check the CSRF token::
+
+    if ($this->isCsrfTokenValid('token_id', $submittedToken)) {
+        // ... do something, like deleting an object
+    }
+
+.. versionadded:: 2.6
+    The ``isCsrfTokenValid()`` shortcut method was introduced in Symfony 2.6.
+    It is equivalent to executing the following code:
+
+    .. code-block:: php
+
+        use Symfony\Component\Security\Csrf\CsrfToken;
+
+        $this->get('security.csrf.token_manager')
+            ->isTokenValid(new CsrfToken('token_id', 'TOKEN'));
+
 Final Thoughts
 --------------