further minor manpage fixes

ksh.1tbl

@@ -1,4 +1,4 @@
-.\" $MirBSD: ksh.1tbl,v 1.24 2004/05/23 12:47:00 tg Exp $
+.\" $MirBSD: ksh.1tbl,v 1.25 2004/05/23 13:01:35 tg Exp $
 .\" $OpenBSD: ksh.1tbl,v 1.70 2004/05/09 06:07:42 otto Exp $
 .\"
 .\" Copyright (c) 1980, 1990, 1993
@@ -975,8 +975,7 @@ and
 .Sq D .
 Note that if the
 .Ev IFS
-parameter is set to the
-.Dv NULL
+parameter is set to the null
 string, no field splitting is done; if the parameter is unset, the default
 value of space, tab, and newline is used.
 .Pp
@@ -1054,7 +1053,8 @@ or
 where
 .Ar name
 is a parameter name.
-If substitution is performed on a parameter (or an array parameter element)
+If substitution is performed on a parameter
+(or an array parameter element)
 that is not set, a null string is substituted unless the
 .Ic nounset
 option