DOC: 'MS' offset alias does not work as described with pd.date_range()
- [x] closes #44146 
- [x] tests added / passed
- [x] 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
- [NA] whatsnew entry
