TST: Allow for multiple variables on the same line in docstring validation
Allow for multiple variables to share the same type and description in documentation. For example, `i, j, k : int` Would be three variables, i, j, and k, which are all ints.

- [ ] tests added / passed 
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry - I'm not sure how to add this, if it needs done could I get a pointer?
