clarify Transaction prose test version requirements and collection creation (#1777)

Author: nbbeeken

source/transactions/tests/README.md

@@ -84,16 +84,19 @@ these tests do not run against a standalone server.
 ### 1.0 Write concern not inherited from collection object inside transaction.
 
 - Create a MongoClient running against a configured sharded/replica set/load balanced cluster.
+    - transactions require a 4.0+ server when non-sharded and 4.2+ when sharded
 - Start a new session on the client.
 - Start a transaction on the session.
 - Instantiate a collection object in the driver with a default write concern of `{ w: 0 }`.
+    - Create the collection or ensure it exists before the insert
 - Insert the document `{ n: 1 }` on the instantiated collection.
 - Commit the transaction.
 - End the session.
 - Ensure the document was inserted and no error was thrown from the transaction.
 
 ## Changelog
 
+- 2025-03-27: Clarify server versions and collection creation for prose test
 - 2024-10-31: Add test for PoolClearedError.
 - 2024-02-15: Migrated from reStructuredText to Markdown.
 - 2024-02-07: Converted legacy transaction tests to unified format and moved the legacy test format docs to a separate