update Sphinx config

[terencehonles]

Pulling changes out of #144

Fixes this:

To this:

If you're using Sphinx > 4.1 you can use autodoc_typehints as both instead of description as I had initially put in #144 and you put in ed0d3cc, if not you should leave description since both is not understood and will become signature.

The autoclass_content = "both" does not actually seem like it's needed either anymore or maybe at all, but it's something I've run into before and is confusing that that isn't the default behavior. It will concatenate any docstring in __init__ and in the class body in order to document the class. There doesn't seem to be any documentation in the __init__ so it's unneeded, but it doesn't hurt to have so you don't have potentially future documentation get ignored.

See:

• https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html#confval-autoclass_content
• https://www.sphinx-doc.org/en/master/usage/extensions/autodoc.html#confval-autodoc_typehints

[terencehonles]

Just calling out so it doesn't get burried in the PR description, this requires Sphinx 4.1 and probably shouldn't be changed on older versions.

[kislyuk]

This change does not appear to be necessary. I prefer to put type hints in the description, not signature, to keep the signature more readable. And with the current configuration, sphinx already renders the type hints in the parameter description correctly (see https://kislyuk.github.io/watchtower/#watchtower.CloudWatchLogHandler).