mat stepper custom icon edit

1<mat-vertical-stepper>
2  <ng-template matStepperIcon="edit">
3    <mat-icon>insert_drive_file</mat-icon>
4  </ng-template>
5
6  <ng-template matStepperIcon="done">
7    <mat-icon>done_all</mat-icon>
8  </ng-template>
9
10  <!-- Custom icon with a context variable. -->
11  <ng-template matStepperIcon="number" let-index="index">
12    {{index + 10}}
13  </ng-template>
14
15  <!-- Stepper steps go here -->
16</mat-vertical-stepper>