.arcconfig

config: simplify aliasing commands.update.check

experimental.updatecheck was renamed into commands.update.check, use the
config system to provides the fallback on the old config name instead of
adding more code.

Differential Revision: https://phab.mercurial-scm.org/D1117

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