doc: remove unnecessary stability specifiers

If a top level module is listed as Stable, there is no need to
call out individual components of that module as Stable. The
extra text is just distracting.

PR-URL: #28485
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

doc/api/dns.md

@@ -591,8 +591,6 @@ earlier ones time out or result in some other error.
 
 ## DNS Promises API
 
-> Stability: 2 - Stable
-
 The `dns.promises` API provides an alternative set of asynchronous DNS methods
 that return `Promise` objects rather than using callbacks. The API is accessible
 via `require('dns').promises`.

doc/api/fs.md

@@ -3726,8 +3726,6 @@ this API: [`fs.write(fd, string...)`][].
 
 ## fs Promises API
 
-> Stability: 2 - Stable
-
 The `fs.promises` API provides an alternative set of asynchronous file system
 methods that return `Promise` objects rather than using callbacks. The
 API is accessible via `require('fs').promises`.

doc/api/stream.md

@@ -1319,8 +1319,6 @@ changes:
     description: Symbol.asyncIterator support is no longer experimental.
 -->
 
-> Stability: 2 - Stable
-
 * Returns: {AsyncIterator} to fully consume the stream.
 
 ```js