Rst linting

[jakkdl]

Fixes #282 (comment)
Adds https://pypi.org/project/sphinx-lint/ and fixes all errors pointed out by it.
Also fixing a broken bullet list I manually noticed

I did not add any of the following linters, but that could be revisited

• https://github.com/rstcheck/rstcheck which pointed out the markdown url in changelog.rst, but it was otherwise very noisy and didn't point out any actual errors.

• https://github.com/PyCQA/doc8 complains about a ton of lines being too long, so if we want to stick with a max char line length it's the tool to go for. I personally feel it's got much less of an upside compared to code, and can be a major hassle to reflow lines after editing them instead of just letting autowrap handle it.

• https://github.com/twolfson/restructuredtext-lint appears to have very few and very specific rules (that I'm guessing are mostly covered by one or more of the above linters)

[Zac-HD]

Nice!