Fixed #21141 -- Update Sphinx URL

The documentation in _build/html/index.html can then be viewed in a web browser.

[1] http://docutils.sourceforge.net/rst.html

[2] http://sphinx.pocoo.org/

[2] http://sphinx-doc.org/

# branch, which is located at this URL.

intersphinx_mapping = {

    'python': ('http://docs.python.org/2.7', None),

    'sphinx': ('http://sphinx.pocoo.org/', None),

    'sphinx': ('http://sphinx-doc.org/', None),

    'six': ('http://pythonhosted.org/six/', None),

    'simplejson': ('http://simplejson.readthedocs.org/en/latest/', None),

}

is based on docutils__. The basic idea is that lightly-formatted plain-text

documentation is transformed into HTML, PDF, and any other output format.

__ http://sphinx.pocoo.org/

__ http://sphinx-doc.org/

__ http://docutils.sourceforge.net/

To actually build the documentation locally, you'll currently need to install

Besides the `Sphinx built-in markup`__, Django's docs defines some extra

description units:

__ http://sphinx.pocoo.org/markup/desc.html

__ http://sphinx-doc.org/markup/desc.html

* Settings::

* Add `info field lists`__ where appropriate.

  __ http://sphinx.pocoo.org/markup/desc.html#info-field-lists

  __ http://sphinx-doc.org/markup/desc.html#info-field-lists

* Whenever possible, use links. So, use ``:setting:`ADMIN_FOR``` instead

  of ````ADMIN_FOR````.

    Generation of the Django documentation will work with Sphinx version 0.6

    or newer, but we recommend going straight to Sphinx 1.0.2 or newer.

__ http://sphinx.pocoo.org/

__ http://sphinx-doc.org/

__ http://www.gnu.org/software/make/

.. _differences-between-doc-versions:

    have Sphinx installed, build the HTML yourself from the

    documentation files bundled with Django.

.. _Sphinx: http://sphinx.pocoo.org/

.. _Sphinx: http://sphinx-doc.org/

.. _online: https://docs.djangoproject.com/

Along with these new features, the Django team has also been hard at