.arcconfig

dirstate: split a not-so-one-liner

This is shorter and simpler to read.

Differential Revision: https://phab.mercurial-scm.org/D10925

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