title: Angular Material Datepicker - nextClicked, previousClicked not emitting
body: <p>I am trying to use material datepicker to allow users to make a booking. I would like to call an internal method when the user clicks next or previous month in the datepicker. I can see the methods nextClicked and previousClicked but these do not seem to be emitted so i cant perform my own actions.</p>
  
  <pre><code>&lt;input class="date-selected" [matDatepickerFilter]="checkInFilter" [matDatepicker]="checkInDatepicker" [min]="minDate" (focus)="checkInDatepicker.open()" [(ngModel)]="checkInDate"&gt;
  &lt;mat-datepicker #checkInDatepicker (nextClicked)="nextMonth($event)"
      (previousClicked)="previousMonth($event)"&gt;
  &lt;/mat-datepicker&gt;
  </code></pre>
  
  <pre><code>nextMonth(event) {
      console.log(event);
  }
  
  previousMonth(event) {
      console.log(event);
  }
  </code></pre>
  
  <p>Is there anyway to call my own method when a user clicks on next/previous in the datepicker?</p>