Adjust where the date sits under the signature, so that the date isn't
squashed down such that it touches the hrule line underneath it.

Context: I actually made this change on November 3rd, as part of
building a contract document that day.  However, I forgot to push the
change then, and later it was in the way when I needed to pull from
upstream.  Rather than create a merge commit, I just saved the patch
and re-applied it.  So if you're at OTS and you're wondering about the
motivation for this change, look for a contract build on 2020-11-03.