Suggest topic names in revup amend

[jerry-skydio]

Users might like to know their previous topics so that they can either make a commit in the same topic, or make a commit relative to a topic. Similarly we can suggest previous commonly used reviewers and labels.

This information can be populated in the # commented out block when editing the commit message

Also add "revup commit" that is essentially the same as "revup amend --insert" and will bring these features to new commits as well.

[jerry-skydio]

thanks for taking this on

some other suggestions for follow-up changes:

--same-topic flag, when used automatically appends a "Topic:" line with the same topic as the most recent commit
--relative-topic flag that's similar, but appends an empty "Topic:" and a "Relative:" with the previous topic
--new-topic flag appends only an empty "Topic:"

these flags could also add "Reviewers:", "Assignees:", "Labels:" lines

--same-topic doesn't need to add anything since those lines would have been set in a previous commit
--relative-topic matches reviewers, assignees, labels, of the relative topic if they were set
--new-topic appends empty reviewers, assignees, labels. maybe start out commented out?

[malcolm-leclair-skydio]

I'd also love to replicate functionality like git commit -m "Commit Msg" so you can make a quick revup commit without opening an editor like revup commit -m "Quick commit message" -t "topic_name" -r "jerry-skydio"

[jerry-skydio]

further enhancements tracked in #63