minor #5441 [Contributing] remove mailing list and forum references (…

…xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Contributing] remove mailing list and forum references

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

As Stack Overflow is now the preferred web based support platform and
both the mailing list and the forum will be shut down, we should not
refer to them anymore.

Commits
-------

f2fa53b remove mailing list and forum references

contributing/code/bugs.rst

@@ -14,8 +14,8 @@ Before submitting a bug:
 * Double-check the official :doc:`documentation </index>` to see if you're not misusing the
   framework;
 
-* Ask for assistance on the `users mailing-list`_, the `forum`_, or on the
-  #symfony `IRC channel`_ if you're not sure if your issue is really a bug.
+* Ask for assistance on `Stack Overflow`_ or on the #symfony `IRC channel`_
+  if you're not sure if your issue is really a bug.
 
 If your problem definitely looks like a bug, report it using the official bug
 `tracker`_ and follow some basic rules:
@@ -34,8 +34,7 @@ If your problem definitely looks like a bug, report it using the official bug
 
 * *(optional)* Attach a :doc:`patch <patches>`.
 
-.. _users mailing-list: http://groups.google.com/group/symfony2
-.. _forum: http://forum.symfony-project.org/
-.. _IRC channel: irc://irc.freenode.net/symfony
+.. _`Stack Overflow`: http://stackoverflow.com/questions/tagged/symfony2
+.. _IRC channel: http://symfony.com/irc
 .. _tracker: https://github.com/symfony/symfony/issues
 .. _Symfony Standard Edition: https://github.com/symfony/symfony-standard/

contributing/code/security.rst

@@ -9,9 +9,9 @@ Reporting a Security Issue
 --------------------------
 
 If you think that you have found a security issue in Symfony, don't use the
-mailing-list or the bug tracker and don't publish it publicly. Instead, all
-security issues must be sent to **security [at] symfony.com**. Emails sent to
-this address are forwarded to the Symfony core-team private mailing-list.
+bug tracker and don't publish it publicly. Instead, all security issues must
+be sent to **security [at] symfony.com**. Emails sent to this address are
+forwarded to the Symfony core-team private mailing-list.
 
 Resolving Process
 -----------------