It's great to see more git documentation, and I have a lot of respect for Beej's Guide to Network Programming. However he really needs to work on his commit hygiene. I get that this is a one-man project, but still it's pretty atrocious: https://github.com/beejjorgensen/bggit/commits/main/. This does not set a good example.
I usually refer people to https://cbea.ms/git-commit/.