message: docs: add developer survey 2021
  PR Close
diff: <mat-toolbar color="primary" class="app-toolbar no-print" [class.transitioning]="isTransitioning">
  <mat-toolbar-row class="notification-container">
  - <aio-notification notificationId="survey-march-2020" expirationDate="2020-04-15" [dismissOnContentClick]="true" (dismissed)="notificationDismissed()">
  - <a href="https://goo.gle/angular-survey-2020">
  + <aio-notification notificationId="survey-october-2021" expirationDate="2021-11-10" [dismissOnContentClick]="true" (dismissed)="notificationDismissed()">
  + <a href="https://goo.gle/angular-survey-2021">
  <mat-icon class="icon" svgIcon="insert_comment" aria-label="Announcement"></mat-icon>
  <span class="message">Help Angular by taking a <b>1 minute survey</b>!</span>
  <span class="action-button">Go to survey</span>
  