Avoid Saxon genitive for objects and add link for clarification

wiki/src/news/version_2.9.mdwn

@@ -33,8 +33,8 @@ Do not use the <i>Synaptic</i> package manager.
 Do not use the <tt>apt-get</tt> or <tt>apt</tt> commands in the terminal.
 </li>
 <li>
-Do not use Tails' <i>Additional software packages</i> feature
-(<tt>live-additional-software.conf</tt>).
+Do not use the [[<i>Additional software packages</i> persistence
+feature|doc/first_steps/persistence/configure#additional_software]].
 </li>
 </ul>