debug-revlog: details about non-ancestors delta-bases
Deltas against a base that is not an ancestor of the revision that owns this
delta are notable.
For example, they introduce complexity during the bundling process as the base
might not exist on the unbundling side.
We detect them in `hg debugrevlog` and print information about them.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}