DOCSP-29400 Add RustTab to transactions page (#3170)

Author: ianf-mongodb

source/core/transactions.txt

@@ -216,6 +216,18 @@ upper-right to set the language of the following example.
          :start-after: Start Transactions withTxn API Example 1
          :end-before: End Transactions withTxn API Example 1
 
+   .. tab::
+      :tabid: rust
+
+      .. include:: /includes/transactions/example-intro.rst
+
+      .. include:: /includes/extracts/transactions-example-note.rst
+
+      .. literalinclude:: /driver-examples/mod.rs
+         :language: rust
+         :dedent: 4
+         :start-after: Start Transactions withTxn API Example 1
+         :end-before: End Transactions withTxn API Example 1
 
    .. tab::
       :tabid: go