DOC: Improve docs in the dt namespace

[rhshadrach]

Ref: #59878 (comment)

E.g. https://pandas.pydata.org/docs/dev/reference/api/pandas.Series.dt.to_period.html

We currently copy the docstring from the underlying array method, which is at times either vague or incorrect as in the example above. We could instead override the docstring with custom value in pandas/core/accessor.py in the _create_delegator_method function. We would need a place to store the docstrings, and it would be a significant effort to add them all.

Possible approach: Create a new subdirectory, pandas/core/docstrings/ for storing docstrings for purposes like this, and add series_dt.py there. It would contain a dictionary mapping the method name to the docstring.

[saldanhad]

#59671

[Rahul20037237]

can I take this?

[rhshadrach]

Discussed on the last dev call, the plan here is to improve the docstrings on the underlying array methods so that additional and highly redundant documentation does not need to be added. I plan to update the OP with a list of methods and instructions for updating the docstrings. Once that is up, work can commence.