Run automated code formatter to standardize library coding style

[tsalo]

Summary

This stems from #466 (comment) and #446 (review). The coding style is very variable across the repository, so it would be helpful to standardize this with an automated code formatter, like black.

To do this, we need to merge current PRs and not open any new ones before the formatting PR is merged. I think we should ping the creators of the current PRs to see where they're at and whether they'd be willing to deal with the merge conflicts on their end.

[tsalo]

To start, I think that #333, #441, #454, and #461 are small enough that the authors can just deal with the merge conflicts after the fact, while #446 is fairly large and should probably be dealt with beforehand.