add some missing punctuation and add another documentation resource

src/bin/keactrl/keactrl.xml

@@ -181,17 +181,19 @@
       <citerefentry>
         <refentrytitle>kea-dhcp4</refentrytitle>
         <manvolnum>8</manvolnum>
-      </citerefentry>
+      </citerefentry>,
 
       <citerefentry>
         <refentrytitle>kea-dhcp6</refentrytitle>
         <manvolnum>8</manvolnum>
-      </citerefentry>
+      </citerefentry>,
 
       <citerefentry>
         <refentrytitle>kea-dhcp-ddns</refentrytitle>
         <manvolnum>8</manvolnum>
-      </citerefentry>
+      </citerefentry>,
+
+      <citetitle>Kea Administrator's Guide</citetitle>.
 
     </para>
   </refsect1>