rust-requirements: allow loading repos with `bookmarksinstore` requirement `rhg` does support bookmarks, so it can load repos with the `bookmarksinstore` requirement just as well as other repos. Differential Revision: https://phab.mercurial-scm.org/D12425

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