Docsp 28559 reuse mongoclient (#250)

* DOCSP-28559: recommend reusing Client

* add Faq question

* update

* JS PR fixes 1

* terminology fix

Author: rustagir

source/faq.txt

@@ -86,7 +86,7 @@ to become available.
 The driver does not limit the number of operations that
 can wait for sockets to become available and it is the application's
 responsibility to limit the size of its pool to bound queuing
-during a load spike. Threads can wait for any length of time
+during a load spike. Operations can wait for any length of time
 unless you define the ``waitQueueTimeoutMS`` option.
 
 An operation that waits more than the length of time defined by