update method reference

Author: stephmarie17

source/fundamentals/transactions.txt

@@ -214,8 +214,7 @@ To see a fully runnable example that uses this API, see the
 
       If you're using {+mdb-server+} v8.0 or later, you can perform
       write operations on multiple namespaces within a single transaction by using
-      the ``bulkWrite()`` method. For more information,
-      see the :ref:`<node-usage-bulk>` guide.
+      the ``client.bulkWrite()`` method.
 
 .. _nodejs-transaction-settings: