DOCS-14888 setFeatureCompatibilityVersion wtimeout (mongodb#6167)

Co-authored-by: jason-price-mongodb <jshfjghsdfgjsdjh@aolsdjfhkjsdhfkjsdf.com>

Author: jason-price-mongodb

source/reference/command/setFeatureCompatibilityVersion.txt

@@ -27,7 +27,10 @@ The command takes the following form:
 
 .. code-block:: javascript
 
-   db.adminCommand( { setFeatureCompatibilityVersion: <version> } )
+   db.adminCommand( {
+      setFeatureCompatibilityVersion: <version>,
+      writeConcern: { wtimeout: <timeout> }
+   } )
 
 The values for the ``version`` are:
 
@@ -119,6 +122,18 @@ The values for the ``version`` are:
        Disables the :ref:`3.4 features that persist data
        incompatible with MongoDB 3.2 <3.4-compatibility-enabled>`.
 
+The optional ``writeConcern`` specifies the write concern
+:ref:`wc-wtimeout` value in milliseconds:
+
+- The time period that the :term:`primary` waits for
+  acknowledgment from the majority of the replica set members. If the
+  acknowledgment is not received in the time period, the operation
+  fails.
+
+- Default is ``60000`` milliseconds. Use a longer time period if the
+  :term:`secondary` members of the replica set have a delay that exceeds
+  the :ref:`wc-wtimeout` default.
+
 .. note::
 
    .. include:: /includes/list-run-command-targets.rst
@@ -494,3 +509,23 @@ Set Feature Compatibility Version on MongoDB 3.4 Deployments
             If performed as part of a downgrade to 3.2 procedure, you must also
             manually remove the existing usage before downgrading the binaries. For
             details, see :ref:`3.4-downgrade-features-prereq`.
+
+Set Write Concern Timeout
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The following example sets the optional write concern :ref:`wc-wtimeout`
+field to 5000 (5 seconds).
+
+.. note::
+
+   Run the :dbcommand:`setFeatureCompatibilityVersion` command against
+   the ``admin`` database.
+
+   .. include:: /includes/list-run-command-targets.rst
+
+.. code-block:: javascript
+
+   db.adminCommand( {
+      setFeatureCompatibilityVersion: "4.4",
+      writeConcern: { wtimeout: 5000 }
+   } )