DOCSP-21243 retryable writes enabled by default (#194)

* DOCSP-21243 retryable writes

* Staging fixes

* Review feedback

Author: Dave

source/reference/compatibility.txt

@@ -112,6 +112,14 @@ specified for the operation:
 In the legacy ``mongo`` shell, these operations use the specified read
 preference.
 
+Write Preference Behavior
+-------------------------
+
+:ref:`Retryable writes <retryable-writes>` are enabled by default in
+:binary:`mongosh`. Retryable writes were disabled by default in the
+legacy :binary:`mongo` shell. To disable retryable writes, use 
+:option:`--retryWrites=false <mongosh --retryWrites>`.
+
 Numeric Values
 --------------
 

source/reference/options.txt

@@ -452,8 +452,10 @@ Session Options
 
 .. option:: --retryWrites
 
-   Enables :manual:`retryable writes </core/retryable-writes/>` as the
-   default for sessions in the |mdb-shell|.
+   Enables :ref:`retryable-writes`. Retryable writes are enabled by
+   default in :binary:`mongosh`. Retryable writes are disabled by
+   default in the legacy :binary:`mongo` shell. To disable retryable
+   writes, use :option:`--retryWrites=false <mongosh --retryWrites>`.
 
    For more information on sessions, see :ref:`sessions`.