Improve make_transform_adapt docstring

[jessegrabowski]

This PR does two things:

1. I added a minimial docstring to make_transform_adapt to give a basic outline of each parameter (as I understand them), and try to explain situations in which they will not be respected.
2. I added a @wraps(make_transform_adapt) decorator to PyFuncModel.with_transform_adapter to expose this docstring there as well. This is the primary entrypoint to the transform adapt functionality for users, so it's important that help(PyFuncModel.with_transform_adapter) gives back something.

There are several parameters I marked with ??? because I don't really know what they do. @aseyboldt I'm happy to fill them out if you can give me a thumbnail sketch of what they do