wording and spelling

src/app/components/shared/room-join/room-join.component.html

@@ -6,7 +6,7 @@
              onkeydown="if(this.value.length - (this.value.split(' ').length -1) === 8 && event.keyCode != 8) return false;
                         if(this.value.length === 4 && event.keyCode != 8) this.value = this.value + ' ';"
                         [formControl]="roomFormControl" [errorStateMatcher]="matcher"/>
-      <mat-placeholder class="placeholder">Session-ID</mat-placeholder>
+      <mat-placeholder class="placeholder">Session ID</mat-placeholder>
       <mat-hint align="end">{{ roomId.value.length - (roomId.value.split(' ').length -1) }} / 8</mat-hint>
       <mat-error *ngIf="roomFormControl.hasError('required')">{{ 'home-page.please-enter' | translate}}</mat-error>
       <mat-error *ngIf="roomFormControl.hasError('pattern')">{{ 'home-page.only-numbers' | translate}}</mat-error>