This is a copy of the TortoiseHg configuration, but dropping the 3-way diff and
dirdiff settings (since those aren't supported in core Mercurial), and swapping
the 'parent1', 'parent2', and 'base' literals for $labellocal, `$labelother,
and $labelbase respectively. (That functionality was apparently never ported
to TortoiseHg.)
Additionally, the single quotes were removed from around these arguments, since
none of the other configs have them.