message: docs(operators): scan
  missing number$
diff: @@ -35,9 +35,11 @@ export function scan<V, A, S>(accumulator: (acc: A | S, value: V, index: number)
  * first value from the source.
  *
  * ```ts
  - * import { interval } from 'rxjs';
  + * import { interval, of } from 'rxjs';
  * import { scan, map } from 'rxjs/operators';
  *
  + * const numbers$ = of(1, 2, 3);
  + *
  * numbers$
  * .pipe(
  * // Get the sum of the numbers coming in.
  