title: Tooltip onTap rather than onLongPress possible?
body: <p>there's no named parameters to configure a single tap to trigger Tooltip,</p>
  
  <p>my feeling about the default longPress interaction is that users cannot find this deep-buried function. </p>
  
  <p>I tried to find some hint in <a href="https://github.com/flutter/flutter/blob/master/packages/flutter/lib/src/material/tooltip.dart" rel="nofollow noreferrer">tooltip source code</a> but failed. </p>
  
  <pre><code> Tooltip(
     message: 'this is something',
     child: SizedBox(...),
   )
  </code></pre>