Thanks so much for the static files feature; it simplifies deployment for my hobby project!

I think it would be nice to have support for pre-compressed static files in the static file server, like nginx's gzip_static directive.

When enabled, a request matching a static file with an appropriate Accept-Encoding header would also check for files matching the path with a .gz, .br, or .zst suffix and respond with the smallest matching compressed version and appropriate Content-Encoding and Vary headers.

Please let me know if you think this feature makes sense for Granian. I'm still new to Rust, but I'd be happy to make a PR if interested!