doc: remove stability warning in v8 module doc

Remove note indicating that the APIs can change at any time. This module
migrated from Experimental to Stable 6 years ago (in io.js 1.4.2).

PR-URL: #35774
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>

Author: Trott

doc/api/v8.md

@@ -11,8 +11,6 @@ built into the Node.js binary. It can be accessed using:
 const v8 = require('v8');
 ```
 
-The APIs and implementation are subject to change at any time.
-
 ## `v8.cachedDataVersionTag()`
 <!-- YAML
 added: v8.0.0