adding role button and columnheader

Author: MPopov

projects/igniteui-angular/src/lib/calendar/days-view/days-view.component.html

@@ -1,8 +1,8 @@
 <div role="row" class="igx-calendar__body-row">
-    <div aria-hidden="true" *ngIf="showWeekNumbers" class="igx-calendar__label igx-calendar__label--week-number">
+    <div role="columnheader" *ngIf="showWeekNumbers" class="igx-calendar__label igx-calendar__label--week-number">
         <span>Wk</span>
     </div>
-    <span role="columnheader"  [attr.aria-label]="dayName" *ngFor="let dayName of generateWeekHeader()" class="igx-calendar__label">
+    <span role="columnheader" [attr.aria-label]="dayName" *ngFor="let dayName of generateWeekHeader()" class="igx-calendar__label">
         {{ dayName | titlecase }}
     </span>
 </div>

projects/igniteui-angular/src/lib/calendar/months-view/months-view.component.html

@@ -1,6 +1,7 @@
 <div class="igx-calendar__body">
     <div  class="igx-calendar__body-row--wrap">
         <span
+            role="button"
             [attr.aria-label]="month | date: 'LLLL'"
             [igxCalendarMonth]="month"
             [date]="date"