title: GAS: prompt for user input with a default value
body: <p>Consider the following Google apps script code:</p>
  
  <pre><code>var ui = SpreadsheetApp.getUi();
  var result = ui.prompt(
     'How many days in advance you want to receive the event notification?',
     '',
     ui.ButtonSet.OK_CANCEL);  
  </code></pre>
  
  <p>I would like the dialog to show a default value in the input box.<br>
  Secondly, do we have keyboard shortcuts to enter/send data? So that the user can hit <kbd>Enter</kbd> (or the likes) to accept the default or <code>value</code>-<kbd>Enter</kbd>  to send his/her own values.</p>