doc,n-api: mark napi_detach_arraybuffer as experimental

As its actual release stage.

PR-URL: #30703
Backport-PR-URL: #33061
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

Author: legendecas

doc/api/n-api.md

@@ -2953,6 +2953,8 @@ of the ECMAScript Language Specification.
 added: REPLACEME
 -->
 
+> Stability: 1 - Experimental
+
 ```C
 napi_status napi_detach_arraybuffer(napi_env env,
                                     napi_value arraybuffer)