Docs: Update the 'require' and 'exports' interfaces usage guides

[dynst]

#5357 seems to be moving towards an ESM-first Mocha 12+. Should the require and exports interfaces be removed, renamed, or have their documentation updated to demonstrate how to use them with ESM syntax?

mocha/docs-next/src/content/docs/interfaces/exports.mdx

Lines 19 to 22 in b1f1cb7

	module.exports = {
	before: function () {
	// ...
	},

mocha/docs-next/src/content/docs/interfaces/require.mdx

Lines 10 to 14 in cafa782

	The `require` interface cannot be run via the `node` executable, and must be run via `mocha`.
	:::
	```js
	var testCase = require("mocha").describe;

[JoshuaKGoldberg]

This is an interesting one. I could see this going in two directions:

• Big overhaul ("removed, renamed, ...") - I believe out of scope for Mocha. We're not planning on removing any major API portions that end-users have historically used.
• Docs touchups ("documentation updated"): This would be good. The pages still show module.exports = and don't link to standalone examples.

For the docs note, we're working on a new docs site (#5576, etc.) and planning on auditing the docs in general. So I'll mark this as a core-team issue for now. We'll plan to tackle it in the new year. Thanks for filing!