DOC: Clarify where to the additional arguments for some win_types
For example, std needs to specify when win_types is gaussian. However, std should be specified in the operation argument, not as one of the rolling arguments. This change is to clarify this point. 

- [ ] closes #34593
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry
