Added a sphinx build to the tox configuration, and fixed a warning in the docs…

Added a sphinx build to the tox configuration, and fixed a warning in the docs (thanks to Justin Lilly for the assist).

docs/external_apps.txt

@@ -12,13 +12,15 @@ of interest.
 
 
 If you have an application that you'd like to see listed here, simply fork
-``taggit`` on `github <http://github.com/alex/django-taggit>`_, add it to this
-list, and send a pull request.
+``taggit`` on `github`__, add it to this list, and send a pull request.
 
  * ``django-taggit-suggest``: Provides support for defining keyword and regular
    expression rules for suggesting new tags for content.  This used to be
-   available at ``taggit.contrib.suggest``.  Available on
-   `github <http://github.com/frankwiles/django-taggit-suggest>`_.
+   available at ``taggit.contrib.suggest``.  Available on `github`__.
  * ``django-taggit-templatetags``: Provides several templatetags, including one
    for tag clouds, to expose various ``taggit`` APIs directly to templates.
-   Available on `github <http://github.com/feuervogel/django-taggit-templatetags>`_.
+   Available on `github`__.
+
+__ http://github.com/alex/django-taggit
+__ http://github.com/frankwiles/django-taggit-suggest
+__ http://github.com/feuervogel/django-taggit-templatetags

tox.ini

 [tox]
-envlist = py25, py26 , py27, pypy, py25-trunk, py26-trunk, py27-trunk, pypy-trunk
+envlist =
+    py25, py26 , py27, pypy, py25-trunk, py26-trunk, py27-trunk, pypy-trunk, docs
 [testenv]
-commands = python setup.py test
+commands =
+    python setup.py test
 deps =
     django==1.2.3
 
@@ -27,3 +29,10 @@ deps =
 basepython = pypy
 deps =
     http://www.djangoproject.com/download/1.3-alpha-1/tarball/
+
+[testenv:docs]
+changedir = docs
+deps =
+    sphinx
+commands =
+    sphinx-build -W -b html -d {envtmpdir}/doctrees . {envtmpdir}/html