Post 9.0.0 Quality of Life Improvements

Heya, now that 9.0.0 is out of the way, I’d like to propose a number of quality of life improvements made. Please assign yourself if you like to tackle them.

- [ ] rename `master` to `main` to adjust with the new reality. I keep finding my muscle memory getting in the way :) (Assignee: @janl)
- [ ] test: don’t run full test suite when changes were only made to the documentation
- [ ] commits: start using and enforce [semantic-release-style](https://github.com/semantic-release/semantic-release) commit messages. This will unify our change log and help auto generate release notes. This reduces the time we need to spend making actual releases. I’m not suggesting we start using semantic-release for the project, just take the structured commit messages from this. It’d be great if we had a git commit hook and PR action to auto-lint commit messages, so folks have an easier time with this.

What other quality-of-life improvements would you like to see?