unexpand the mdocdate keyword in gotweb.conf.5
diff --git a/gotweb/gotweb.conf.5 b/gotweb/gotweb.conf.5
index 43132a3..62d2057 100644
--- a/gotweb/gotweb.conf.5
+++ b/gotweb/gotweb.conf.5
@@ -13,7 +13,7 @@
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
-.Dd $Mdocdate: January 15 2020 $
+.Dd $Mdocdate$
.Dt GOTWEB.CONF 5
.Os
.Sh NAME