Use entity references to unify fixed sentences

Author: KentarouTakeda

reference/pgsql/functions/pg-set-chunked-rows-size.xml

@@ -45,7 +45,7 @@
  <refsect1 role="returnvalues">
   &reftitle.returnvalues;
   <simpara>
-   Returns &true; on success or &false; on failure.
+   &return.success;
   </simpara>
  </refsect1>