DOCSP-48609-add-mongosync-notes

Author: gmiller-mdb

source/reference/limitations.txt

@@ -150,6 +150,9 @@ Sharded Clusters
   returns an error and stops, which requires you to start the migration
   from scratch.
 
+- :dbcommand:`transitionFromDedicatedConfigServer` is not supported during 
+  ``mongosync`` execution.
+
 - You must not run the :dbcommand:`moveChunk` and
   :dbcommand:`moveRange` commands on the source or destination clusters.
 - The shard key cannot be :ref:`refined <shard-key-refine>` while