cleanup: prefer nested context managers to \-continuations
I'd prefer Python accept a tuple of context managers, but alas it
isn't meant to be. This will have to suffice.
Differential Revision: https://phab.mercurial-scm.org/D5994
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}