Remove "Print" from keys that can open F8 menu

Since it is caught by the local system on most platforms.
diff --git a/vncviewer/vncviewer.man b/vncviewer/vncviewer.man
index d6a3708..b1450d1 100644
--- a/vncviewer/vncviewer.man
+++ b/vncviewer/vncviewer.man
@@ -257,8 +257,7 @@
 .B \-MenuKey \fIkeysym-name\fP
 This option specifies the key which brings up the popup menu. The currently
 supported list is: F1, F2, F3, F4, F5, F6, F7, F8, F9, F10, F11, F12, Pause,
-Print, Scroll_Lock, Escape, Insert, Delete, Home, Page_Up, Page_Down).
-Default is F8.
+Scroll_Lock, Escape, Insert, Delete, Home, Page_Up, Page_Down). Default is F8.
 .
 .TP
 \fB\-via\fR \fIgateway\fR