[DOC BLD FIX] Fix docstring error in fakes.rst
In fakes.rst there was a 'todo' directive which
does not work with the latest version of Sphinx.
This fix changes that so that Sphinx doesn't produce
a warning.
Fake Drivers
============
-.. todo:: document general info about fakes
+TODO: document general info about fakes
When the real thing isn't available and you have some development to do these
fake implementations of various drivers let you get on with your day.
