Add Build Output API Edge Middleware REWRITE Example

[AaronBeaudoin]

Not much to say here. It'd be nice to have a Build Output API example of using Edge Middleware to rewrite the URL, including the query string.

[lfades]

There's a basic edge-middleware example with the Build Output API here: https://github.com/vercel/examples/tree/main/build-output-api/edge-middleware. Our documentation isn't very clear and it's Next.js focused, cc @TooTallNate what can we do to improve this?