DOCSP-45882: Transactions parallelism admonition (#104)

Author: mcmorisi

source/write/transactions.txt

@@ -134,6 +134,15 @@ completes the following actions:
       Insert completed: AcknowledgedInsertOneResult{insertedId=BsonObjectId{value=...}}
       Update completed: AcknowledgedUpdateResult{matchedCount=1, modifiedCount=1, upsertedId=null}
 
+.. sharedinclude:: dbx/transactions-parallelism.rst
+
+   .. replacement:: driver-specific-content
+
+      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:`<scala-bulk-write>`
+      guide.
+
 Additional Information
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