Fix psql's \d and allied commands to work with all server versions back to 7.4.

Guillaume Lelarge, with some additional fixes by me.

doc/src/sgml/ref/psql-ref.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.208 2008/06/11 10:48:16 heikki Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.209 2008/07/03 03:37:16 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -2859,26 +2859,22 @@ $endif
       <para>
        In an earlier life <application>psql</application> allowed the
        first argument of a single-letter backslash command to start
-      directly after the command, without intervening whitespace. For
-      compatibility this is still supported to some extent,
-      but we are not going to explain the details here as this use is
-      discouraged.  If you get strange messages, keep this in mind.
-      For example:
-<programlisting>
-testdb=&gt; <userinput>\foo</userinput>
-Field separator is "oo".
-</programlisting>
-      which is perhaps not what one would expect.
+       directly after the command, without intervening whitespace.
+       As of <productname>PostgreSQL</productname> 8.4 this is no
+       longer allowed.
       </para>
       </listitem>
 
       <listitem>
       <para>
-      <application>psql</application> only works smoothly with servers
-      of the same version. That does not mean other combinations will
-      fail outright, but subtle and not-so-subtle problems might come
+       <application>psql</application> is only guaranteed to work smoothly
+       with servers of the same version. That does not mean other combinations
+       will fail outright, but subtle and not-so-subtle problems might come
        up.  Backslash commands are particularly likely to fail if the
-      server is of a different version.
+       server is of a newer version than <application>psql</> itself.  However,
+       backslash commands of the <literal>\d</> family should work with
+       servers of versions back to 7.4, though not necessarily with servers
+       newer than  <application>psql</> itself.
       </para>
       </listitem>