chistedit: explain which order the commits are presented in It's not obvious which order the commits in chistedit (and text-based histedit), so let's add a note about it. Differential Revision: https://phab.mercurial-scm.org/D11832

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "phabricator.uri": "https://phab.mercurial-scm.org/",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}