Solving that issue isn't trivial. I just read it and I wouldn't know where to begin, probably because I don't understand the requirements.
I think what's being called "trivial" is doing a bit of regex searching. It's probably accurate to call that trivial for an experienced Rust programmer, but if you're just beginning, I don't think it's helpful to call anything trivial. I still remember my first exposure to Rust. It was different. It took a bit to grok. But once it clicked, things were much better.
As the maintainer of the regex crate, I invite you or anyone to ask for help using regexes. The regex repo has Discussions opened up, so it's appropriate to ask for help, even if they are beginner questions: https://github.com/rust-lang/regex/discussions
As usual though, try to provide as many details as you can. Giving the source code you have but can't get to work is a great start, for example.
