add docker note (#253)

Author: jordan-smith721

source/connect/connection-targets.txt

@@ -164,6 +164,10 @@ tab to see the corresponding code:
          uri = "mongodb://host1:27017/?replicaSet=sampleRS"
          client = AsyncMongoClient(uri)
 
+.. note:: Replica Set in Docker
+
+   .. sharedinclude:: dbx/docker-replica-set.rst
+
 {+driver-short+} evenly load balances operations across deployments that are reachable
 within the client's ``localThresholdMS`` value. To learn more about how {+driver-short+} load
 balances operations across multiple MongoDB deployments, see the