tests: use [(] instead of \( to avoid warning on py3
From a recent test run of mine:
run-tests.py:1633: DeprecationWarning: invalid escape sequence '\('
This lets us encode the expectation without the badness.
Differential Revision: https://phab.mercurial-scm.org/D3621
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}