doc: add call-once note to napi_queue_async_work

Add note to `napi_queue_async_work()` indicating that, upon successful
return, it must not be called again with the same work item.

Fixes: #27217
PR-URL: #27582
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

doc/api/n-api.md

@@ -4060,7 +4060,8 @@ napi_status napi_queue_async_work(napi_env env,
 Returns `napi_ok` if the API succeeded.
 
 This API requests that the previously allocated work be scheduled
-for execution.
+for execution. Once it returns successfully, this API must not be called again
+with the same `napi_async_work` item or the result will be undefined.
 
 ### napi_cancel_async_work
 <!-- YAML