doc: document http2 timeouts

New default timeout values of "2 minutes" were added into documentation
inside 2 classes under "Event: 'timeout'":
1) Class: Http2SecureServer
2) Class: Http2Server

New sections for `.setTimeout()` method were added inside
`Http2SecureServer` & `Http2Server` docs.

Backport-PR-URL: #22850
PR-URL: #22798
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/http2.md

@@ -1604,6 +1604,7 @@ added: v8.4.0
 
 The `'timeout'` event is emitted when there is no activity on the Server for
 a given number of milliseconds set using `http2server.setTimeout()`.
+**Default:** 2 minutes.
 
 #### server.close([callback])
 <!-- YAML
@@ -1617,6 +1618,24 @@ Note that this is not analogous to restricting new requests since HTTP/2
 connections are persistent. To achieve a similar graceful shutdown behavior,
 consider also using [`http2session.close()`] on active sessions.
 
+#### server.setTimeout([msecs][, callback])
+<!-- YAML
+added: v8.4.0
+-->
+
+* `msecs` {number} **Default:** `120000` (2 minutes)
+* `callback` {Function}
+* Returns: {Http2Server}
+
+Used to set the timeout value for http2 server requests,
+and sets a callback function that is called when there is no activity
+on the `Http2Server` after `msecs` milliseconds.
+
+The given callback is registered as a listener on the `'timeout'` event.
+
+In case of no callback function were assigned, a new `ERR_INVALID_CALLBACK`
+error will be thrown.
+
 ### Class: Http2SecureServer
 <!-- YAML
 added: v8.4.0
@@ -1717,6 +1736,7 @@ added: v8.4.0
 
 The `'timeout'` event is emitted when there is no activity on the Server for
 a given number of milliseconds set using `http2secureServer.setTimeout()`.
+**Default:** 2 minutes.
 
 #### Event: 'unknownProtocol'
 <!-- YAML
@@ -1740,6 +1760,24 @@ Note that this is not analogous to restricting new requests since HTTP/2
 connections are persistent. To achieve a similar graceful shutdown behavior,
 consider also using [`http2session.close()`] on active sessions.
 
+#### server.setTimeout([msecs][, callback])
+<!-- YAML
+added: v8.4.0
+-->
+
+* `msecs` {number} **Default:** `120000` (2 minutes)
+* `callback` {Function}
+* Returns: {Http2SecureServer}
+
+Used to set the timeout value for http2 secure server requests,
+and sets a callback function that is called when there is no activity
+on the `Http2SecureServer` after `msecs` milliseconds.
+
+The given callback is registered as a listener on the `'timeout'` event.
+
+In case of no callback function were assigned, a new `ERR_INVALID_CALLBACK`
+error will be thrown.
+
 ### http2.createServer(options[, onRequestHandler])
 <!-- YAML
 added: v8.4.0