Fix apt_preferences(5) example to match text

debian/changelog

@@ -3,6 +3,8 @@ apt (0.5.31) unstable; urgency=low
   * New Romanian translation from Sorin Batariuc <sorin@bonbon.net>
     (Closes: #281458)
   * Merge changes from Hoary (0.5.30,0.5.30ubuntu2]
+  * Fix the example in apt_preferences(5) to match the text
+    (Closes: #222267)
 
  --
 

doc/apt_preferences.5.xml

@@ -192,8 +192,8 @@ and whose release Version number is "<literal>3.0</literal>".</simpara>
 
 <programlisting>
 Package: *
-Pin: release a=unstable, v=3.0
-Pin-Priority: 50
+Pin: release a=stable, v=3.0
+Pin-Priority: 500
 </programlisting>
 </listitem>
 </itemizedlist>