Update doc related with HTTP/2

Signed-off-by: raccoonback <[email protected]>

Author: raccoonback

docs/modules/ROOT/pages/http-client.adoc

@@ -318,6 +318,7 @@ include::{examples-dir}/http2/H2Application.java[lines=18..42]
 ----
 <1> Configures the client to support only `HTTP/2`
 <2> Configures `SSL`
+<3> You can configure the interval for checking `Ping` frames
 
 The following listing presents a simple `H2C` example:
 

reactor-netty-examples/src/main/java/reactor/netty/examples/documentation/http/client/http2/H2Application.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2021 VMware, Inc. or its affiliates, All Rights Reserved.
+ * Copyright (c) 2020-2025 VMware, Inc. or its affiliates, All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,13 +21,16 @@
 import reactor.netty.http.client.HttpClient;
 import reactor.util.function.Tuple2;
 
+import java.time.Duration;
+
 public class H2Application {
 
 	public static void main(String[] args) {
 		HttpClient client =
 				HttpClient.create()
 				          .protocol(HttpProtocol.H2) //<1>
-				          .secure();                 //<2>
+				          .secure()                 //<2>
+						  .http2Settings(builder -> builder.pingInterval(Duration.ofMillis(100))); // <3>
 
 		Tuple2<String, HttpHeaders> response =
 				client.get()