Convert bins to numeric for histogram if a string
Fixes #29484

- [ ] closes #29484
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Yes I'll work on creating a test. can you merge master and add a test @wesbarnett does this type of bins handling come from other packages? We only have this documented as working for `integer or sequence` @WillAyd it comes from matplotlib where you can pass things like "auto". See #29484. Makes sense. Can you update the docstring as well then?  Hello @wesbarnett! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:







There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2020-10-03 13:13:30 UTC @WillAyd I only see the docstring for hist indicating an integer is supported. I've added a blurb taken from the matplotlib docstring to indicate that a string is supported.

I actually misspoke in my last comment - this is provided by numpy's histogram method, which matplotlib uses.

Is sequence also supported? @wesbarnett can you take a look at last round of comments? @wesbarnett this also needs a whatnew note (bug fixes plotting in 1.1), pls ping on green when ready. > @wesbarnett can you take a look at last round of comments?

@WillAyd See the previous thread. I think I addressed everything other than whatsnew entry. Sorry if I missed anything. @wesbarnett can you merge master Merged master to fix the upstream CI issue.

@wesbarnett do we have a test for this that uses `.plot.hist()`? @TomAugspurger No test for `.plot.hist()` in this. I can add some. @jreback Okay, should be good now. I merged master again. @wesbarnett merging master should fix the CI failures. @wesbarnett is this still active? Can you move note to 1.2? @WillAyd @jreback this is ready for review. One of the builds failed to run. Not sure how to retrigger that. ping @WillAyd @jreback 

@wesbarnett can you merge master again? closing as stale. this looks like an ok soln, though likely needs some more tests.