title: Display Date and time on highcharts
body: <p>I have the following data </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>firstData = [  
  ["2019-11-24", "12:38:54"],
   ["2019-11-21", "07:06:29"],
   ["2019-11-20", "19:26:37"],
   ["2019-09-26", "19:56:00"] ]
  
  secondData = [ 
  ["2019-09-26", "10:26:00"],
   ["2019-11-20", "06:52:34"],
   ["2019-11-21", "07:06:19"],
   ["2019-11-24", "07:38:54"] ]</code></pre>
  </div>
  </div>
  </p>
  
  <p>I would like to display graph like this.
  <a href="https://i.stack.imgur.com/utNzQ.png" rel="nofollow noreferrer">date and time graph</a></p>