Update rouge to 3.15.0

Bump Rouge

This adds a few new lexers: FreeFEM, GHC, and Objective-C++.

This also includes a bunch of fixes, including for Jinja, Rust, Python, TOML, BPF, and Swift.

https://github.com/rouge-ruby/rouge/releases

Full diff: https://github.com/rouge-ruby/rouge/compare/v3.11.0..v3.15.0