Tweak wording of DISCARD ALL description to avoid giving the impression

that the presented list of equivalent operations is meant to be the
primary definition of what it does.  Per comment from Guillaume Smet.

doc/src/sgml/ref/discard.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/discard.sgml,v 1.4 2008/11/26 01:21:07 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/discard.sgml,v 1.5 2008/11/27 00:28:06 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -71,9 +71,9 @@ DISCARD { ALL | PLANS | TEMPORARY | TEMP }
     <listitem>
      <para>
       Releases all temporary resources associated with the current
-      session and resets the session to its initial state. This has
-      the same effect as executing the following sequence of
-      statements:
+      session and resets the session to its initial state.
+      Currently, this has the same effect as executing the following sequence
+      of statements:
 <programlisting>
 SET SESSION AUTHORIZATION DEFAULT;
 RESET ALL;