Generate a "Changes" section from commit history

[reillyeon]

Documenting changes is necessary as part of the transition process. This can be maintained manually but it's easier for editors if it can be generated automatically from the commit history.

ReSpec has this feature: https://respec.org/docs/#rs-changelog

[tabatkins]

Oooh, interesting. That's very doable. (I never would have thought of that, since CSSWG does everything in one repo; we'd have to filter very heavily.)