Docstring modification

[caspervdw]

This started already in PR #18 (@lschr) How would we like to let Slicerator and Pipeline change the docstrings?

[danielballan]

@tacaswell has recently given some thought to this in matplotlib. I don't recall his thinking well enough to accurately summarize. Tom, if you have time, can you summarize and/or link to wherever docstring dicusssions are taking place in mpl?

[tacaswell]

matplotlib/matplotlib#7179