Docs 16242 Abort Expired Transaction Metrics (#4653) (#10545)

* DOCS-16242 abortExpiredTransactions serverStatus

Author: kennethdyer

source/reference/command/serverStatus.txt

@@ -1477,6 +1477,9 @@ metrics
 .. code-block:: javascript
 
    metrics : {
+      abortExpiredTransactions: {
+         passes: <integer>
+      },
       apiVersions: {
          <appName1>: <string>, 
          <appName2>: <string>, 
@@ -1724,6 +1727,19 @@ metrics
    A document that returns various statistics that reflect the current
    use and state of a running :binary:`~bin.mongod` instance.
 
+.. serverstatus:: metrics.abortExpiredTransactions
+
+   Document that returns statistics on the current state of the
+   ``abortExpiredTransactions`` thread.
+
+.. serverstatus:: metrics.abortExpiredTransactions.passes
+
+   Indicates the number of successful passes aborting transactions
+   older than the :parameter:`transactionLifetimeLimitSeconds` parameter.
+
+   If the ``passes`` value stops incrementing, it indicates that the
+   ``abortExpiredTransactions`` thread may be stuck.
+
 .. serverstatus:: metrics.aggStageCounters
 
    A document that reports on the use of