title: Yii2 gridview: render summary if the search returned no results
body: <p>In yii2 in gridview is a search result count (named <code>summary</code>):</p>
  
  <p>Set in gridview: </p>
  
  <pre><code>'summary' =&gt; "Showing {begin} - {end} of {totalCount} items"
  </code></pre>
  
  <p>Displayed above the table (for example):</p>
  
  <pre><code>Showing `1-2` of `2` items.
  </code></pre>
  
  <p>But when the search does not give any results, then the <code>summary</code> is not displayed. And I need to display (if empty search):</p>
  
  <pre><code>Showing `0-2` of `2` items.
  </code></pre>
  
  <p>I can not find in the settings how to display it (if empty search). Help please.</p>