histedit: remove an unnecessary default value of `b''` for commit message I don't think `ctx.description()` is ever anything falsy other than `b''`. I think the comment added in 4c4232e51167 (histedit: extract common summary code into method, 2016-05-27) is mistaken (I don't see any code following that pattern before the function was added). Differential Revision: https://phab.mercurial-scm.org/D12406