histedit: use 'util.ellipsis' to trim description of each changesets Before this patch, trimming description of each changesets in histedit may split at intermediate multi-byte sequence. This patch uses 'util.ellipsis' to trim description of each changesets instead of directly slicing byte sequence. Even though 'util.ellipsis' adds '...' as ellipsis when specified string is trimmed (= this changes result of trimming), this patch uses it, because: - it can be used without any additional 'import', and - ellipsis seems to be better than just trimming, for usability