<!-- Thank you for contributing to Dojo. Our issue tracker is for bugs for Dojo. Please make sure you have read our Contributing Guidelines available at: https://github.com/dojo/meta/blob/master/CONTRIBUTING.md For general questions and discussion, join us on [Discord](https://discord.gg/M7yRngE) --> **Enhancement** <!-- delete as appropriate --> Add documentation for the focus middleware mock added in #635.
