DOC: fixed contrib package name for std/EE

Author: Liudmila Mantrova

doc/src/sgml/contrib.sgml

@@ -45,9 +45,8 @@
  </para>
 
  <para>
-  If you are using a pre-packaged version of <productname>&project;</>,
-  these modules are typically made available as a separate subpackage,
-  such as <literal>postgresql-contrib</>.
+  In <productname>&project;</>, these modules are made available as a separate
+  subpackage <filename>postgrespro-&edn;-&majorversion;-contrib</filename>.
  </para>
 
  <para>