Awesome!
Really looking forward to being able to connect multiple controllers in Reicast.
I don’t have advanced knowledge of Github, but if you clone the repository, make your suggested changes then submit a pull request with a comment explaining what you fixed, that should be all there is to it!
There is a style guide on Github for the project:
https://github.com/RetroPie/RetroPie-Setup/wiki/Shell-Style-Guide