- We don't install USD docs for games anymore since the games with docs

(trek) aren't in the base system anymore.
- dm(8) isn't in the base system anymore either, so don't xref it either.

Submitted by:	Björn König (2)

share/man/man6/intro.6

@@ -49,18 +49,12 @@ command:
 $ apropos '\\(6\\)'
 .Ed
 .Sh FILES
-.Bl -tag -width /usr/share/doc/usd/31.trek -compact
+.Bl -tag -width /usr/games -compact
 .It Pa /usr/games
 location of games
-.It Pa /usr/share/doc/usd
-games tutorials
 .El
 .Sh SEE ALSO
-.Xr intro 1 ,
-.Xr dm 8
-.Pp
-Tutorials in the
-.%T "UNIX User's Manual Supplementary Documents" .
+.Xr intro 1
 .Sh HISTORY
 The
 .Nm