message: Refactor expandable-div
diff: </button>
  </ng-template>
  -<div class="clickable" (click)="notify()">
  - <h1 *ngIf="headerTag == 'h1'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h1>
  - <h2 *ngIf="headerTag == 'h2'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h2>
  - <h3 *ngIf="headerTag == 'h3'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h3>
  - <h4 *ngIf="headerTag == 'h4'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h4>
  - <h5 *ngIf="headerTag == 'h5'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h5>
  - <h6 *ngIf="headerTag == 'h6'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h6>
  - <span class="bold" *ngIf="headerTag == 'text'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></span>
  +<div class="clickable" (click)="notify()" [ngSwitch]="headerTag">
  + <h1 *ngSwitchCase="'h1'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h1>
  + <h2 *ngSwitchCase="'h2'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h2>
  + <h3 *ngSwitchCase="'h3'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h3>
  + <h4 *ngSwitchCase="'h4'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h4>
  + <h5 *ngSwitchCase="'h5'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h5>
  + <h6 *ngSwitchCase="'h6'"><ng-container *ngTemplateOutlet="innerContent"></ng-container></h6>
  + <span *ngSwitchCase="'text'" class="bold"><ng-container *ngTemplateOutlet="innerContent"></ng-container></span>
  </div>
  