Do not use automatic title in fixture reference

It creates odd wording otherwise. Keep the reference, update the title
using Sphinx notation.

doc/en/cache.rst

@@ -194,7 +194,7 @@ The new config.cache object
 
 Plugins or conftest.py support code can get a cached value using the
 pytest ``config`` object.  Here is a basic example plugin which
-implements a :ref:`fixture` which re-uses previously created state
+implements a :ref:`fixture <fixture>` which re-uses previously created state
 across pytest invocations:
 
 .. code-block:: python

doc/en/example/index.rst

@@ -15,7 +15,7 @@ For basic examples, see
 
 - :doc:`../getting-started` for basic introductory examples
 - :ref:`assert` for basic assertion examples
-- :ref:`fixtures` for basic fixture/setup examples
+- :ref:`Fixtures <fixtures>` for basic fixture/setup examples
 - :ref:`parametrize` for basic test function parametrization
 - :doc:`../unittest` for basic unittest integration
 - :doc:`../nose` for basic nosetests integration

doc/en/faq.rst

@@ -32,7 +32,7 @@ just run your tests even if you return Deferreds.  In addition,
 there also is a dedicated `pytest-twisted
 <https://pypi.org/project/pytest-twisted/>`_ plugin which allows you to
 return deferreds from pytest-style tests, allowing the use of
-:ref:`fixtures` and other features.
+:ref:`fixtures <fixtures>` and other features.
 
 how does pytest work with Django?
 ++++++++++++++++++++++++++++++++++++++++++++++