minor symfony#5579 [3.0] Remove mentions of Symfony1 (WouterJ)

This PR was merged into the master branch.

Discussion
----------

[3.0] Remove mentions of Symfony1

I think with Symfony 3, we should no longer document how Symfony >1 differs from Symfony 1.

| Q | A
| --- | ---
| Doc fix? | no
| New docs? | no
| Applies to | 3.0+
| Fixed tickets | -

Commits
-------

feb2ab1 Remove mentions of Symfony1

cookbook/event_dispatcher/before_after_filters.rst

@@ -8,10 +8,10 @@ It is quite common in web application development to need some logic to be
 executed just before or just after your controller actions acting as filters
 or hooks.
 
-In symfony1, this was achieved with the preExecute and postExecute methods.
-Most major frameworks have similar methods but there is no such thing in Symfony.
-The good news is that there is a much better way to interfere with the
-Request -> Response process using the :doc:`EventDispatcher component </components/event_dispatcher/introduction>`.
+Some web frameworks define methods like ``preExecute()`` and ``postExecute()``,
+but there is no such thing in Symfony. The good news is that there is a much
+better way to interfere with the Request -> Response process using the
+:doc:`EventDispatcher component </components/event_dispatcher/introduction>`.
 
 Token Validation Example
 ------------------------

cookbook/index.rst

@@ -29,7 +29,6 @@ The Cookbook
     service_container/index
     session/index
     psr7
-    symfony1
     templating/index
     testing/index
     upgrade/index

cookbook/map.rst.inc

@@ -211,10 +211,6 @@
 
   * :doc:`/cookbook/psr7`
 
-* **symfony1**
-
-  * :doc:`/cookbook/symfony1`
-
 * :doc:`/cookbook/templating/index`
 
   * :doc:`/cookbook/templating/global_variables`