Improve documentation for CounterField.
Review Request #9753 — Created March 7, 2018 and submitted
The CounterField documentation was lacking, and misleading in some
places. This simply fleshes out the docs to better match our current doc
There's a few small styling tweaks in the code as well to help tidy a few
Built the docs and checked for errors.
All unit tests in Djblets and Review Board pass.
Fixed a stylng error from moving a variable to a keyword argument.
Revision 2 (+232 -48)
Checks run (2 succeeded)