message: docs(concatAll): fix map import
diff: @@ -32,7 +32,7 @@ export function concatAll<R>(): OperatorFunction<any, R>;
  * For each click event, tick every second from 0 to 3, with no concurrency
  * ```javascript
  * import { fromEvent, interval } from 'rxjs';
  - * import { ma, take, concatAll } from 'rxjs/operators';
  + * import { map, take, concatAll } from 'rxjs/operators';
  *
  * const clicks = fromEvent(document, 'click');
  * const higherOrder = clicks.pipe(
  