DATACMNS-205 - Fix broken reference documentation.

The section on the repository exporters contained a code sample using language="javascript". As the highlighting in the docbkx plugin doesn't support javascript as language it will break the build of other reference documents including this one. Removed the language attribute for this sample entirely.

src/docbkx/repositories.xml

@@ -1070,7 +1070,7 @@ public class UserController {
       <example>
         <title>Data defined in JSON</title>
 
-        <programlisting language="javascript">[ { "_class" : "com.acme.Person",
+        <programlisting>[ { "_class" : "com.acme.Person",
  "firstname" : "Dave",
   "lastname" : "Matthews" },
   { "_class" : "com.acme.Person",