doc: update websocket flag description to reflect stable API status

Author: debbs061

doc/api/cli.md

@@ -1637,7 +1637,7 @@ Use this flag to disable top-level await in REPL.
 added: v22.0.0
 -->
 
-Use this flag to disable experimental [`WebSocket`][] support.
+Disable exposition of [`WebSocket`][] on the global scope.
 
 ### `--no-extra-info-on-fatal-exception`