DOCSP-35753 server status metric step down moved to state transaction v4.4 backport (manual) (#6069)

* Manual backport due to refactor.

* Fixing formatting for new code example edits.

Author: mmaville-mdb

source/reference/command/serverStatus.txt

@@ -4053,7 +4053,8 @@ metrics
                 "num" : <NumberLong>
             }
          },
-         "stepDown" : {
+         "stateTransition" : {
+            "lastStateTransition" : <string>,
             "userOperationsKilled" : <NumberLong>,
             "userOperationsRunning" : <NumberLong>
          },
@@ -4565,26 +4566,50 @@ metrics
       Replica set members in the :replstate:`STARTUP2` state do not send
       the ``replSetUpdatePosition`` command to their sync source.
 
-.. serverstatus:: metrics.repl.stepDown
+.. serverstatus:: metrics.repl.stateTransition
 
-   Information on user operations that were running when the
-   :binary:`~bin.mongod` stepped down.
+   Information on user operations when the member undergoes one of the
+   following transitions that can stop user operations:
 
-   .. versionadded:: 4.2
+    - The member steps up to become a primary.
 
-.. serverstatus:: metrics.repl.stepDown.userOperationsKilled
+    - The member is actively performing a rollback.
 
-   The number of user operations killed when the :binary:`~bin.mongod`
-   stepped down.
+.. serverstatus:: metrics.repl.stateTransition.lastStateTransition
+   
+   The transition being reported:
+   
+   .. list-table::
+      :widths: 20 80
+      :header-rows: 1
+      
+      * - State Change
+        - Description
 
-   .. versionadded:: 4.2
+      * - ``"stepUp"``
 
-.. serverstatus:: metrics.repl.stepDown.userOperationsRunning
+        - The member steps up to become a primary.
 
-   The number of user operations that remained running when the
-   :binary:`~bin.mongod` stepped down.
+      * - ``"stepDown"``
+        - The member steps down to become a secondary.
 
-   .. versionadded:: 4.2
+      * - ``"rollback"``
+
+        - The member is actively performing a rollback.
+
+      * - ``""``
+
+        - The member has not undergone any state changes.
+
+.. serverstatus:: metrics.repl.stateTransaction.userOperationsKilled
+
+   The number of user operations stopped during the
+   :binary:`~bin.mongod` instance's state change.
+
+.. serverstatus:: metrics.repl.stateTransaction.userOperationsRunning
+
+   The number of user operations that remained running during the
+   ``mongod`` instance's state change.
 
 .. serverstatus:: metrics.repl.syncSource