📝 Docs: Explicitly document how to work with Node loader/import/require flags

[JoshuaKGoldberg]

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

Collecting user questions from #5002 & #5047 & linked: it's not clear in the Mocha docs how to use it in conjunction with Node.js --(experimental-)loader (deprecated), --import, and/or --require. I think it'd be good to put a docs guide somewhere. This area of user questioning has become much more relevant over the last few years as ESM's gotten more popular. Folks writing TypeScript more and more has been a factor too.

Additional Info

mochajs/mocha-examples#76 will help but is really only part of the way.

I'm not sure exactly where to put these docs 🤔. Something to think about once start to look at the website more critically.