Git se fusiona con el mensaje
$ git merge other-branch -m "Commit Message"
Lively Ladybird
$ git merge other-branch -m "Commit Message"For current Git versions (2020+), just do git rebase -i -r <parent>,
then replace in the editor merge -C with merge -c.
This will open the merge commit's message in the editor during rebasing,
where you can change it