DOCSP-46695: Add extra info on load balancing to connection targets page (#164)

(cherry picked from commit ce4843c)

Author: mcmorisi

source/connect/connection-targets.txt

@@ -9,7 +9,7 @@ Choose a Connection Target
    :values: reference
 
 .. meta::
-   :keywords: connection string, URI, server, settings, client
+   :keywords: connection string, URI, server, settings, client, load balancing
 
 .. contents:: On this page
    :local:
@@ -74,6 +74,15 @@ Replica Sets
 To connect to a replica set, specify the hostnames (or IP addresses) and 
 port numbers of the replica-set members in your connection string.
 
+The following code shows how to use {+driver-short+} to connect to a replica set
+that contains three hosts:
+
+.. code-block:: python
+
+   from pymongo import MongoClient
+   
+   client = MongoClient("mongodb://host1:27017,host2:27017,host3:27017")
+
 If you aren't able to provide a full list of hosts in the replica set, you can 
 specify one or more of the hosts in the replica set and instruct {+driver-short+} to 
 perform automatic discovery to find the others. To instruct the driver to perform
@@ -94,6 +103,11 @@ hosts, including ``host1``:
    uri = "mongodb://host1:27017/?replicaSet=sampleRS"
    client = MongoClient(uri)
 
+{+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
+:ref:`pymongo-server-selection` guide.
+
 .. note::
 
    The ``MongoClient`` constructor is *non-blocking*.