process: graduate process.ref/unref from experimental

These have been shipped and stable since v22/v23

Signed-off-by: James M Snell <jasnell@gmail.com>
PR-URL: #66213
Reviewed-By: Gürgün Dayıoğlu <hey@gurgun.day>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: jasnell

doc/api/process.md

@@ -3328,10 +3328,12 @@ console.log(`The parent process is pid ${ppid}`);
 added:
   - v23.6.0
   - v22.14.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/66213
+    description: This API is no longer experimental.
 -->
 
-> Stability: 1 - Experimental
-
 * `maybeRefable` {any} An object that may be "refable".
 
 An object is "refable" if it implements the Node.js "Refable protocol".
@@ -4431,10 +4433,12 @@ In [`Worker`][] threads, `process.umask(mask)` will throw an exception.
 added:
   - v23.6.0
   - v22.14.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/66213
+    description: This API is no longer experimental.
 -->
 
-> Stability: 1 - Experimental
-
 * `maybeRefable` {any} An object that may be "unref'd".
 
 An object is "unrefable" if it implements the Node.js "Refable protocol".