moving extension dev overview

doc/development/tutorials/index.rst

@@ -5,10 +5,6 @@ Extension tutorials
 
 Refer to the following tutorials to get started with extension development.
 
-.. toctree::
-   :caption: General extension tutorials
-
-   overview
 
 .. toctree::
    :caption: Directive tutorials

doc/development/tutorials/overview.rst

@@ -1,32 +0,0 @@
-Developing extensions overview
-==============================
-
-This page contains general information about developing Sphinx extensions.
-
-Make an extension depend on another extension
----------------------------------------------
-
-Sometimes your extension depends on the functionality of another
-Sphinx extension. Most Sphinx extensions are activated in a
-project's :file:`conf.py` file, but this is not available to you as an
-extension developer.
-
-.. module:: sphinx.application
-    :noindex:
-
-To ensure that another extension is activated as a part of your own extension,
-use the :meth:`Sphinx.setup_extension` method. This will
-activate another extension at run-time, ensuring that you have access to its
-functionality.
-
-For example, the following code activates the ``recommonmark`` extension:
-
-.. code-block:: python
-
-    def setup(app):
-        app.setup_extension("recommonmark")
-
-.. note::
-
-   Since your extension will depend on another, make sure to include
-   it as a part of your extension's installation requirements.