Document extra information provided by psql's \dT+ (not \dt+ as per recent commit).

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

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-$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.200 2008/05/02 22:50:21 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/psql-ref.sgml,v 1.201 2008/05/05 01:38:08 adunstan Exp $
 PostgreSQL documentation
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@@ -1145,7 +1145,8 @@ testdb=&gt;
         <para>
         Lists all data types or only those that match <replaceable
         class="parameter">pattern</replaceable>. The command form
-        <literal>\dT+</literal> shows extra information.
+        <literal>\dT+</literal> shows extra information, namely the type's internal name, size, and
+        allowed values for <type>enum</> types.
         </para>
         </listitem>
       </varlistentry>