ENH: add str.removeprefix
- [x] closes #36944
- [ ] tests added / passed
- [x] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing.html#code-standards) for how to run them
- [x] whatsnew entry

Hello @erfannariman! 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 2021-02-12 22:46:27 UTC @erfannariman can you merge master and fixup > @erfannariman can you merge master and fixup

Yes, will do this weekend. Will also want to add an entry to doc/source/reference/series.rst to make sure this renders in the docs yep, pls add to here: https://pandas.pydata.org/pandas-docs/dev/user_guide/text.html#method-summary, optionally add add an example near strip This pull request is stale because it has been open for thirty days with no activity. Please update or respond to this comment if you're still interested in working on this. @erfannariman can you merge master and get tests to pass. also can you add a benchmark.

Is there a benefit to using the builtin if py39 else using the fallback

and also for the fallback is there any benefit to having two maps followed by a np.where over just using the fallback function (len(prefix) is invariant so the mapper function can be defined in a closure)

This does not close the issue? need to add removesuffix also?

This should also work for StringArray. can you use `any_string_dtype` in the tests Thanks @erfannariman for the PR. closing as stale. ping if you want to continue.