 DOC: fix docstring validation errors for pandas.core.window
Partially addresses https://github.com/pandas-dev/pandas/issues/58063.

Fixes:
https://github.com/pandas-dev/pandas/blob/306385b0c157da62595a4b3efb23799b7d136c62/ci/code_checks.sh#L256-L260
Thanks @hlakams 