Formatting guidelines would be good too

As far as I'm aware we currently have neither code nor doc formatting guidelines, but these would definitely be good to have. For code we might want to switch to black at some point (I'm currently using the PyCharm formatter defaults), but for docs we probably just need to agree on something and stick to that. There's the default rst style, numpy and the google style. A comparison of the three can be found further down the napoleon doc page. We already enabled that Sphinx plugin so any of the three styles should work. Personally, I guess I'd prefer the Google style for parameters and the like as it requires the least amount of superfluous formatting and is nicely readable on a screen that is more wide than tall. 😉 @C4ptainCrunch @tomschr opinions?

Originally posted by @N-Coder in #340 (comment)