feat: propose change commitMessage

[Kiruel]

If we want to respect the convention for commit message, the scope should be on first position when exist, then I propose to add the emoji inside the parentheses.

So before this PRs:
:sparkles: feat: commit message

After:
feat(:sparkles:): commit message

[noomly]

Koumu didn't have any plan initially to support a commit convention other than the one it's defining. I'm not against having different conventions available in Koumu though. But implementing this would mean making it configurable and respected both in the hooks and in the cli, which would involve bigger changes than simply editing the output of the commit command. That being said, I don't need this feature myself so I wont personally work on this implementation.