message: docs: fix FormRecord example
  PR Close
diff: @@ -164,7 +164,7 @@ Some `FormGroup` usages do not fit the above pattern because the keys are not kn
  ```ts
  const addresses = new FormRecord<FormControl<string|null>>({});
  -names.addControl('Andrew', new FormControl('2340 Folsom St'));
  +addresses.addControl('Andrew', new FormControl('2340 Folsom St'));
  ```
  Any control of type `string|null` can be added to this `FormRecord`.
  