dirstate-tracked-key: update the config value to match latest discussion
Special cases are not special enough, we align the option name on the other.
The `version` value is undocumented for now as it can only have a single value.
It is supported in the code to properly detect and abort if more value are
introduced in the future value.
Differential Revision: https://phab.mercurial-scm.org/D12184
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}