Cannot use factory constructor in augmented class

```dart
class Bar {
}

augment class Bar {
  const factory Bar() = Foo; // 🔥 warning: error: The name of a factory constructor must be the same as the name of the immediately enclosing class. (invalid_factory_name_not_a_class at [macros_playground] lib/main.dart:26)
}

class Foo implements Bar {
  const Foo();
}
```

The analyzer complains about the line marked with 🔥.