minor #3759 Update templates.rst (Francoscopic)

This PR was submitted for the 3.x branch but it was merged into the 2.x branch instead.

Discussion
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Update templates.rst

Changed "an other strategy" to "another strategy". I assume this latter should be the intended sentence structure.

Commits
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4904f38 Update templates.rst

doc/templates.rst

@@ -441,7 +441,7 @@ Escaping works by using the :doc:`escape<filters/escape>` or ``e`` filter:
     {{ user.username|e }}
 
 By default, the ``escape`` filter uses the ``html`` strategy, but depending on
-the escaping context, you might want to explicitly use an other strategy:
+the escaping context, you might want to explicitly use another strategy:
 
 .. code-block:: twig