amend: adjust the dirstate within a `parentchange` context
The adjustment in the direct consequence of the amend and the associated parents
change.
Differential Revision: https://phab.mercurial-scm.org/D11032
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}