title: How to change angular material stepper step numbers to any icon or text?
body: <p><a href="https://material.angular.io/components/stepper/overview" rel="noreferrer">Angular Material Stepper</a> has following problems for me which I can not found from documentation. </p>
  
  <ol>
  <li>How can I display any string or html instead of stepper index
  numbers? </li>
  <li>How can display <a href="https://material.angular.io/components/tooltip/overview" rel="noreferrer">matToolTip</a> when mouse hover any mat step? </li>
  </ol>
  
  <p>I am using latest version of <a href="https://material.angular.io/" rel="noreferrer">Material Angular IO</a>.</p>