fix GNU groff-only formatting bug in the manpage

From: Jean Delvare <jdelvare@suse.de>

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.427 2017/03/12 02:34:54 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.428 2017/03/14 11:32:56 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.160 2015/07/04 13:27:04 feinerer Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
@@ -76,7 +76,7 @@
 .\" with -mandoc, it might implement .Mx itself, but we want to
 .\" use our own definition. And .Dd must come *first*, always.
 .\"
-.Dd $Mdocdate: March 12 2017 $
+.Dd $Mdocdate: March 14 2017 $
 .\"
 .\" Check which macro package we use, and do other -mdoc setup.
 .\"
@@ -4855,7 +4855,7 @@ This is not done by the otherwise identical
 .Ic global .
 .Em Note :
 This means that
-.Nm No 's Ic global
+.Nm Ns 's Ic global
 command is
 .Em not
 equivalent to other programming languages' as it does not allow a