Documentation Request Checklist

• I have read and agree to Mocha's Code of Conduct and Contributing Guidelines
• I have searched for related issues and issues with the faq label, but none matched my issue.
• I want to provide a PR to resolve this

Overview

The documentation about using mocha in the browser is broken, that the linked chai library does not work in a non-ES-module context.

See also: related issue for chai.

Additional Info

No response