message: Example code is wrong.
  operator map and the first example are wrong.
diff: @@ -18,7 +18,7 @@ For example, the operator called [`map`](/api/operators/map) is analogous to the
  import { of } from 'rxjs';
  import { map } from 'rxjs/operators';
  -map(x => x * x)(of(1, 2, 3)).subscribe((v) => console.log(`value: ${v}`));
  +of(1, 2, 3).pipe(map(x => x * x)).subscribe((v) => console.log(`value: ${v}`));
  // Logs:
  // value: 1
  @@ -33,7 +33,7 @@ will emit `1`, `4`, `9`. Another useful operator is [`first`](/api/operators/fi
  import { of } from 'rxjs';
  import { first } from 'rxjs/operators';
  -first()(of(1, 2, 3)).subscribe((v) => console.log(`value: ${v}`));
  +of(1, 2, 3).pipe(first()).subscribe((v) => console.log(`value: ${v}`));
  // Logs:
  // value: 1
  