### Pull Request Checklist

<!-- Please read CONTRIBUTING.rst before submitting your pull request -->

* [ ] Pull request includes a [changelog file](https://github.com/matrix-org/matrix-spec/blob/master/CONTRIBUTING.rst#adding-to-the-changelog)
* [ ] Pull request includes a [sign off](https://github.com/matrix-org/matrix-spec/blob/master/CONTRIBUTING.rst#sign-off)
* [ ] Pull request is classified as ['other changes'](https://github.com/matrix-org/matrix-spec/blob/master/CONTRIBUTING.rst#other-changes)