histedit: use "editor" argument of "commit()" instead of explicit "ui.edit()" Before this patch, "message" action of "hg histedit" uses "ui.edit()" explicitly to get commit message edited manually. This requires explicit "localrepository.savecommitmessage()" invocation to save edited commit message into ".hg/last-message.txt", because unexpected exception raising may abort command execution before saving it in "localrepository.commit()". This patch uses "editor" argument of "localrepository.commit()" instead of explicit "ui.edit()" invocation for "message" action of "hg histedit" "localrepository.commit()" will invoke "editor()" function newly added in this patch, and save edited commit message into ".hg/last-message.txt" automatically.