KAFKA-19734: Updating the docs for KIP-1221 (#20804)

Updating the docs for the client state metric (KIP-1221).

Reviewers: Matthias Sax<[email protected]>, Bill
 Bejeck<[email protected]>, Chia-Ping Tsai <[email protected]>

Author: gensericghiro

docs/ops.html

@@ -3040,7 +3040,7 @@ <h5 class="anchor-heading"><a id="kafka_streams_client_monitoring" class="anchor
   <tr>
     <td>client-state</td>
     <td>The state of the Kafka Streams client as a number (<code>ordinal()</code> of the corresponding enum).</td>
-    <td>kafka.streams:type=stream-metrics,client-id=([-.\w]+),process-id=([-.\w]+)</td>
+    <td>kafka.streams:type=stream-metrics,client-id=([-.\w]+),process-id=([-.\w]+),application-id=([-.\w]+)</td>
   </tr>
   <tr>
     <td>alive-stream-threads</td>

docs/streams/upgrade-guide.html

@@ -146,6 +146,11 @@ <h3><a id="streams_api_changes_420" href="#streams_api_changes_420">Streams API
         More details can be found in <a href="https://cwiki.apache.org/confluence/x/ywnxFg">KIP-1216</a>.
     </p>
 
+    <p>
+        The <code>application-id</code> tag is now available for the Kafka Streams client state metric (<code>client-state</code>).
+        More details can be found in <a href="https://cwiki.apache.org/confluence/x/jQobFw">KIP-1221</a>.
+    </p>
+
     <h3><a id="streams_api_changes_410" href="#streams_api_changes_410">Streams API changes in 4.1.0</a></h3>
 
     <p><b>Note:</b> Kafka Streams 4.1.0 contains a critical memory leak bug (<a href="https://issues.apache.org/jira/browse/KAFKA-19748">KAFKA-19748</a>) that affects users of range scans and certain DSL operators (session windows, sliding windows, stream-stream joins, foreign-key joins). Users running Kafka Streams should consider upgrading directly to 4.1.1, which includes the fix for it.</p>