title: How to change state icon in Angular Material stepper?
body: <p>I am using Angular Material stepper. Using STEPPER_GLOBAL_OPTIONS, I am able to change the state of the steps like this:</p>
  
  <pre><code>  &lt;mat-step [stepControl]="secondFormGroup" optional state="phone"&gt;
    &lt;/mat-step&gt;
  </code></pre>
  
  <p>However, how do I access the list of these icons? Or, is there any way to use my own?</p>