message: Add description to qustion.getDisplayValue function
diff: @@ -771,6 +771,10 @@ export class Question extends SurveyElement
  if (this.isLoadingFromJson) return;
  this.setPropertyValue("displayValue", this.getDisplayValue(true));
  }
  + /**
  + * Return the question value as a display text. For example, for dropdown, it would return the item text instead of item value.
  + * @param keysAsText Set this value to true, to return key (in matrices questions) as display text as well.
  + */
  public getDisplayValue(keysAsText: boolean): any {
  if (this.customWidget) {
  var res = this.customWidget.getDisplayValue(this);
  