Add a note that the "whiteout inode", DT_WHT, is an implementation detail

and should not be seen in normal user applications.

share/man/man5/dir.5

@@ -1,4 +1,4 @@
-.\"	$NetBSD: dir.5,v 1.23 2010/05/15 15:38:41 jruoho Exp $
+.\"	$NetBSD: dir.5,v 1.24 2010/05/16 08:56:17 jruoho Exp $
 .\"
 .\" Copyright (c) 1983, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)dir.5	8.3 (Berkeley) 4/19/94
 .\"
-.Dd May 15, 2010
+.Dd May 16, 2010
 .Dt DIRENT 5
 .Os
 .Sh NAME
@@ -147,6 +147,11 @@ domain socket
 dummy
 .Dq whiteout inode
 .El
+.Pp
+The
+.Dv DT_WHT
+type is internal to the implementation and
+should not be seen in user applications.
 .It
 The
 .Fa d_name
@@ -181,6 +186,9 @@ operator.
 .Xr fs 5 ,
 .Xr inode 5
 .\" .Sh STANDARDS
+.\"
+.\" XXX: Conformance is unclear, cf. PR lib/43310.
+.\"
 .\" Given the noted limitations, the
 .\".In dirent.h
 .\" header conforms to
@@ -193,12 +201,3 @@ The
 .Em dirent
 structure appeared in
 .Nx 1.3 .
-.\"
-.\" XXX: Unclear, cf. PR lib/43310.
-.\"
-.\" .Sh BUGS
-.\" The
-.\" .Nx
-.\" implementation uses a statically allocated buffer for the
-.\" .Va d_name
-.\" entry.