Get the signed-off-by and co-authored-by info

[tisonkun]

Summary 💡

Nowadays, a Git commit can be a squashed one from multiple commits during a pull request. To respect the commit's authors, neither "the commit author" nor "the commit committer" is completed.

Is it considered in the scope of gix to have a method on Commit to return a list of all signed-of-by and/or co-authored-by signatures.

Motivation 🔦

No response

[EliahKagan]

CommitRef::message_trailers does this, returning a Trailers iterator whose items, of type TrailerRef, represent trailers as token: value.

[Byron]

Thanks @EliahKagan!

I checked and couldn't see that git2 has a convenience function like that, but I think these special trailers are common enough to make them very easy to retrieve.
My feeling is that Trailers should be used, but that there should be an easy way to case-insensitively search or filter for these common TrailerRefs. Maybe the TrailerRef itself could have functions that allow it to check for is_signed_off(&self) for instance.