Add reference to manual chains article for the compile extension

docs/shorewall_extension_scripts.xml

@@ -18,7 +18,7 @@
     <pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
 
     <copyright>
-      <year>2001-2007</year>
+      <year>2001-2010</year>
 
       <holder>Thomas M. Eastep</holder>
     </copyright>
@@ -596,6 +596,9 @@ esac</programlisting><caution>
       <para>Example:</para>
 
       <programlisting>my $chainref = $filter_table-&gt;{INPUT}; #Same as above with a few less keystrokes; runs faster too</programlisting>
+
+      <para>For imformation about the 'compile' extension script, see the
+      <ulink url="ManualChains.html">Manual Chains article</ulink>.</para>
     </section>
   </section>
 </article>