.arcconfig

shortest: use nodetree for finding shortest node within revset

This speeds up `hg log -T '{shortest(node,1)}\n'` in my repo from 12s
to 4.5s. That's very close to the 4.1s it takes without the
disambiguation revset configured. My repo has 69.5k revisions, of
which 550 were in the configured revset ("not public()").

Differential Revision: https://phab.mercurial-scm.org/D4120

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