.arcconfig

cleanup: join string literals that are already on one line

Thanks to Kyle for noticing this and for providing the regular
expression to run on the codebase.

This patch has been reviewed by the test suite and they approved of
it.

# skip-blame: fallout from mass reformatting

Differential Revision: https://phab.mercurial-scm.org/D7028

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