Consider adding a hint parameter

[LrWm3]

Hello!

I added a --hint param to this in a fork I maintain here: https://github.com/LrWm3/ai-commit/tree/main

I find it really helpful as small commits can sometimes really benefit from a bit of context on the "why" of the change, and its still much easier than writing out the full commit message.

I could try and submit a PR if you would consider adding it.

Thanks!