rhg: in path_encode, use Vec directly instead of VecDest
No need to have a trivial wrapper over the type.
There's nothing confusing about vec.write_bytes(...), after all.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}