Add xrefs to crypt(3) and pw(8) and add a warning about not manually

altering passwd related files.

PR:             74656
Submitted by:   Jilles Tjoelker <jilles@stack.nl> (original version)

share/man/man5/passwd.5

@@ -35,7 +35,7 @@
 .\"     From: @(#)passwd.5	8.1 (Berkeley) 6/5/93
 .\" $FreeBSD$
 .\"
-.Dd January 16, 1999
+.Dd February 8, 2005
 .Dt PASSWD 5
 .Os
 .Sh NAME
@@ -61,6 +61,9 @@ and
 as controlled by
 .Xr nsswitch.conf 5 .
 .Pp
+For consistency, none of these files should ever be modified
+manually.
+.Pp
 The
 .Nm master.passwd
 file is readable only by root, and consists of newline separated
@@ -126,7 +129,8 @@ in the user database.
 .Pp
 The password field is the
 .Em encrypted
-form of the password.
+form of the password, see
+.Xr crypt 3 .
 If the
 .Ar password
 field is empty, no password will be required to gain access to the
@@ -335,10 +339,12 @@ BEGIN { FS = ":"}
 .Xr chpass 1 ,
 .Xr login 1 ,
 .Xr passwd 1 ,
+.Xr crypt 3 ,
 .Xr getpwent 3 ,
 .Xr login.conf 5 ,
 .Xr netgroup 5 ,
 .Xr adduser 8 ,
+.Xr pw 8 ,
 .Xr pwd_mkdb 8 ,
 .Xr vipw 8 ,
 .Xr yp 8