tests: show that hg log --debug output differs from {file*} template keywords
hg log --debug -T xml doesn't differ, but let's test it because we can.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}