bug #3509 Fix typo: side.bar.twig => sidebar.twig (ifdattic)

This PR was merged into the 2.3 branch.

Discussion
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Fix typo: side.bar.twig => sidebar.twig

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.3
| Fixed tickets |

Commits
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3b142dd Fix typo: side.bar.twig => sidebar.twig

cookbook/templating/namespaced_paths.rst

@@ -80,4 +80,4 @@ called ``sidebar.twig`` in that directory, you can use it easily:
 
 .. code-block:: jinja
 
-    {% include '@foo_bar/side.bar.twig' %}
+    {% include '@foo_bar/sidebar.twig' %}