Only use emails in .Mt

[Jan Stary]

Index: hack.6
===================================================================
RCS file: /cvs/src/games/hack/hack.6,v
retrieving revision 1.18
diff -u -p -r1.18 hack.6
--- hack.6      13 Mar 2015 19:58:40 -0000      1.18
+++ hack.6      30 Nov 2015 14:14:15 -0000
@@ -211,7 +211,3 @@ wrote the original hack, very much like 
 .An Andries Brouwer
 continuously deformed their sources into the current
 version \(en in fact an entirely different game.
-.Sh BUGS
-Probably infinite.
-Mail complaints to
-.Mt mcvax!aeb .