ENH: Rolling with steps
- [x] closes  #15354
- [ ] tests added / passed
- [ ] Ensure all linting tests pass, see [here](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit) for how to run them
- [ ] whatsnew entry
- [x] update docu
- [ ] docu example
- [ ]  add *versionadded* to docu if accepted
