sharesafe: make warning about outdated share configurable
If the source repository upgrades to use sharesafe mode, we show a warning in
shares. This patch makes that warning configurable and some might not want their
users see this warning.
Differential Revision: https://phab.mercurial-scm.org/D9691
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}