minor #6794 Added a new section to the page templating/global_vars us…

…ing a EVListener (piet, Piet Bijl)

This PR was submitted for the master branch but it was merged into the 2.7 branch instead (closes #6794).

Discussion
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Added a new section to the page templating/global_vars using a EVListener

Added another option for injecting variables into templates through the use of a event listener, also added a DC/removal notice on twigs getGlobals

Commits
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ef1c2fd Added a new section to the page templating/global_vars using a EVListener

templating/global_variables.rst

@@ -124,12 +124,4 @@ This should feel familiar, as it's the same syntax you use in service configurat
              'globals' => array(
                  'user_management' => '@app.user_management',
              ),
-        ));
-
-Using a Twig Extension
-----------------------
-
-If the global variable you want to set is more complicated - say an object -
-then you won't be able to use the above method. Instead, you'll need to create
-a :ref:`Twig Extension <reference-dic-tags-twig-extension>` and return the
-global variable as one of the entries in the ``getGlobals`` method.
+        ));