histedit: drop --no-backup option Dropping this option because now we have a better option than passing --no-backup flag every time, now user can set a config in hgrc: [ui] history-editing-backup = False This config aims to operate on every history editing command and it is still work in progress. As yuya suggessted it probably to late to add full support this config, so making this as an experimental config. Differential Revision: https://phab.mercurial-scm.org/D3965