[Request] Please add option to show shift

[3dsf]

Thanks for working on this project.

I think that when people are following along, they might miss the distinction between r and R, especially when it is a Ctrl+r vs Ctrl+R

Thanks

[AlynxZhou]

Could be done if I have time on this. Soon or later.

[AlynxZhou]

https://github.com/AlynxZhou/showmethekey/commit/3e1be24a71a8a8890741e164ba6937fd9091b947.