Support napoleon and google style docs

[sotte]

I normally sphinx-napoleon and the "google style" for docs. It would be great if sphinx-autodoc-annotation supported this!

class MyClass: pass

def f(x: str, y: MyClass) -> str:
    """
    Do something...

    Args:
        x: some string
        y: something important

    Return:
        the same string
    """
    print(x)
    return x

Currently the output looks like this:

[evanunderscore]

Napoleon works by transforming docstrings, so this may work out of the box if you put sphinx.ext.napoleon before sphinx_autodoc_annotation. I haven't tested it, but the same thing works for sphinx-autodoc-typehints.