updated readme & config to fix a couple of build errors/warnings

Author: jmcmichael

README.md

@@ -11,7 +11,7 @@ We welcome contributions to the documentation. If you wish to contribute a clari
 After you've forked and cloned the repository, install [Sphinx](https://www.sphinx-doc.org/en/master/), a [reStructuredText](http://docutils.sourceforge.net/rst.html) documentation generator, and [sphinx-autobuild](https://pypi.org/project/sphinx-autobuild/), a utility that will host and update the documentation as you work:
 
 ```
-pip install sphinx sphinx-autobuild sphinx-fontawesome sphinxcontrib-images
+pip install sphinx sphinx-autobuild sphinx-fontawesome sphinxcontrib-images sphinx-rtd-theme
 ```
 
 These docs also depend on a custom fork of the `sphinxcontrib-programoutput` extension. It can be installed by running:
@@ -60,8 +60,8 @@ git push origin doc-update
 
 Then visit the [civic-docs pull requests page](https://github.com/griffithlab/civic-docs/pulls). Github should display a message asking you if you'd like to create a pull request from the new branch you just pushed. Create the pull request with a short description of your contribution. A CIViC maintainer will evaluate your contribution and will likely merge it with the master branch, which will then be published. Thanks for your contributions!
 
-
 ## Setting up Sphinx to work in Docker
+
 If you wind up in Python dependency hell getting Sphinx to work, you may want to try working in a Docker image by doing something like the following:
 
 ```
@@ -74,4 +74,3 @@ sphinx-autobuild --host 0.0.0.0 --port 8000 ./ ./_build/html
 ```
 
 To view the updated docs site in your web browser go to: http://0.0.0.0:8000/. Once you are satisfied, submit a pull request as described above.
-

docs/conf.py

@@ -63,7 +63,7 @@
 #
 # This is also used if you do content translation via gettext catalogs.
 # Usually you set "language" from the command line for these cases.
-language = None
+language = 'en'
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.