clearable common task symbol

src/app/pieces/task/task.component.html

@@ -10,7 +10,10 @@
     </div>
 
     <div class="piece-symbolchoice" [class]="displaySymbolChoice">
+        <div class="piece-symbolchoice-header">
             <label>Choisir un symbole de tâche commune :</label>
+            <div><mat-icon fontIcon="delete" (click)="setSymbol('','')"></mat-icon></div>
+        </div>
         <div class="piece-symbolchoice-symbols">
             <mat-icon [style.color]="'#d79297'" fontIcon="favorite" (click)="setSymbol('favorite','#d79297')"></mat-icon>
             <mat-icon [style.color]="'#9ad5ec'" fontIcon="diamond" (click)="setSymbol('diamond','#9ad5ec')"></mat-icon>

src/app/pieces/task/task.component.scss

@@ -64,6 +64,12 @@
             opacity: 0.75;
         }
 
+        &-header {
+            display: flex;
+            flex-direction: row;
+            justify-content: space-between;
+        }
+
         &-symbols {
             display: flex;
             flex-direction: row;