address comment: detail unref usecase

doc/api/readline.md

@@ -628,8 +628,10 @@ the best compatibility if it defines an `output.columns` property and emits
 a `'resize'` event on the `output` if or when the columns ever change
 ([`process.stdout`][] does this automatically when it is a TTY).
 
-In order to end the wait for the `stdin` input stream (so that the program
-does not appear to have hanged), `unref` function can be used:
+When creating a `readline.Interface` using `stdin` as input stream, the program will not
+terminate until it receives `EOF` (<kbd>Ctrl</kbd>+<kbd>D</kbd>). If you want
+your application to exit without waiting for user input, you can `unref` the
+standard input:
 
 ```js
 process.stdin.unref();