doc: graduate Symbol.dispose/asyncDispose from experimental

Now that Symbol.dispose and Symbol.asyncDispose have been
enabled by default and are expected to likely advance to
stage 4 this week, let's graduate them from experimental
status.

PR-URL: https://github.com/nodejs/node/pull/58467
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Dario Piotrowicz <dario.piotrowicz@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>

doc/api/https.md

@@ -137,10 +137,12 @@ See [`server.close()`][] in the `node:http` module.
 
 <!-- YAML
 added: v20.4.0
+changes:
+ - version: REPLACEME
+   pr-url: https://github.com/nodejs/node/pull/58467
+   description: No longer experimental.
 -->
 
-> Stability: 1 - Experimental
-
 Calls [`server.close()`][httpsServerClose] and returns a promise that
 fulfills when the server has closed.