Inheriting docstrings from Pandas in python >= 3.5

[AdamOrmondroyd]

For python >= 3.5, if an overridden function lacks a docstring, then it looks up the inheritance tree to find one.

For example, if one were to delete the docstring from anesthetic.weighted_pandas.WeightedDataFrame.quantile(), then instead we would see the docstring from Pandas through help() or in an IDE such as VS Code.

import anesthetic as ac
ns = ac.read_chains("anesthetic/tests/example_data/pc")
help(ns.quantile)

Perhaps it would be good to make use of this in anesthetic?

[lukashergt]

Thanks for pointing this out! This might resolve (part of) #22.