slighly adjust notification message format

This'll have to do until we get around to support formatted
message bodies.

main.go

@@ -113,7 +113,7 @@ type notifier struct {
 }
 
 func (n *notifier) notify(m chatMessage) error {
-	const notificationFmt = "Incoming support message from %s (%s):\n> %s"
+	const notificationFmt = "# Incoming support message from %s (%s):\n\n> %s\n"
 	msg := fmt.Sprintf(notificationFmt, m.user, m.displayName, m.message)
 	_, err := n.matrix.SendNotice(n.roomID, msg)
 	return err