message: fix(startWith): fix incorrect types
  This change does not effect the user-facing function overloads, so the function's public signature remains unchanged. This incorrect typing was visible in the docs however, so this change can be thought of as a documentation change.
diff: @@ -65,13 +65,13 @@ export function startWith<T, D = T>(...array: Array<D | SchedulerLike>): Operato
  * @method startWith
  * @owner Observable
  */
  -export function startWith<T, D>(...array: Array<T | SchedulerLike>): OperatorFunction<T, T | D> {
  +export function startWith<T, D>(...array: Array<D | SchedulerLike>): OperatorFunction<T, T | D> {
  const scheduler = array[array.length - 1] as SchedulerLike;
  if (isScheduler(scheduler)) {
  // deprecated path
  array.pop();
  - return (source: Observable<T>) => concat(array as T[], source, scheduler);
  + return (source: Observable<T>) => concat(array as D[], source, scheduler);
  } else {
  - return (source: Observable<T>) => concat(array as T[], source);
  + return (source: Observable<T>) => concat(array as D[], source);
  }
  }
  