view .arcconfig @ 38570:2523c0200df4

diff: use `context.diff` to produce diff

We want to make sure `context.diff` if full featured. Using it in the main
diff code path is a good way to do so.

The end goal is to be able to easily compute diff between in-memory context.

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