CLN: shift with freq and fill_value, to_pydatetime returning Series
xref https://github.com/pandas-dev/pandas/pull/52459, https://github.com/pandas-dev/pandas/pull/54818
Going to merge this one. Can follow up if needed > Going to merge this one. Can follow up if needed

I am opening a PR #57469 to add future warning when calling ```to_pytimedelta``` function, but here it seems that you changed the return type to Series and removed all warning-related imports. Do you want me to do the same thing for ```to_pytimedelta```? 