Format docstrings as required

[clorton]

https://docs.idmod.org/projects/doc-guidance/en/latest/docstrings.html

[jonathanhhb]

I've spent some time formatting doc strings lately and it's my observation that so-called numpy-style doc string seems to render best in a pdf (and also probably html) after being processed by sphinx. I imagine google style should also work if you have the right plugins but it wasn't that way for me.