Fix broken markup.

doc/src/sgml/backup.sgml

 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/backup.sgml,v 2.28 2003/08/17 03:14:26 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/backup.sgml,v 2.29 2003/08/17 22:05:13 tgl Exp $
 -->
 <chapter id="backup">
  <title>Backup and Restore</title>
@@ -154,8 +154,10 @@ pg_dump -h <replaceable>host1</> <replaceable>dbname</> | psql -h <replaceable>h
    </important>
 
    <tip>
+    <para>
     Restore performance can be improved by increasing <literal>SORT_MEM</>
     (see <xref linkend="runtime-config-resource-memory">).
+    </para>
    </tip>
   </sect2>