config: use 'experimental.evolution.allowunstable'
Extract 'experimental.evolution' = allowunstable as
'experimental.evolution.allowunstable'.
We keep the new option in the 'experimental.evolution' namespace in order to
stay coherent with other options ('experimental.evolution.bundle-obsmarker'
and 'experimental.evolution.track-operation') ease the renaming as possibly
'evolution.allowunstable'.
Differential Revision: https://phab.mercurial-scm.org/D1150
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}