doc,readline: add missing node protocol in example

PR-URL: #41560
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Mohammed Keyvanzadeh <[email protected]>
Reviewed-By: James M Snell <[email protected]>

Author: Mesteery

doc/api/readline.md

@@ -33,7 +33,7 @@ The following simple example illustrates the basic use of the `readline` module.
 
 ```mjs
 import * as readline from 'node:readline/promises';
-import { stdin as input, stdout as output } from 'process';
+import { stdin as input, stdout as output } from 'node:process';
 
 const rl = readline.createInterface({ input, output });