Fix pasto which broke docs build.

Commit bc5334d8 accidentally
included a second <variablelist> tag for a new list item.

doc/src/sgml/config.sgml

@@ -330,7 +330,6 @@ include 'filename'
       </listitem>
      </varlistentry>
 
-     <variablelist>
      <varlistentry id="guc-recovery-config-directory" xreflabel="recovery_config_directory">
       <term><varname>recovery_config_directory</varname> (<type>string</type>)</term>
       <indexterm>