I've found that storing changelog snippets in the repository is far more scalable (one file per note in a directory). This allows future changes to update changelog entries and reverts to just remove them completely.
There's also enough trouble getting Github and GitLab to support commenting on commit messages (something they should do anyways!) that feedback on release notes stuffed into commit messages is then a third-class process. They can still be collated and gathered just like from the commit messages, but they're actually tracked by git and there's no confusion when backporting changes: the release note comes with it without having to merge with conflict notes, `cherry-pick -x` notes, etc. You're also not limited to a measly single line for describing your change.