Document: OwnedEntities requires AsNoTracking when queried separately

The code below just crashes with "A tracking query projects owned entity without corresponding owner in result. Owned entities cannot be tracked without their owner":

```
.Select(x => new A
{
OwnedEntity = x.OwnedEntity
});

```

It worked fine on EF Core 2. No single word about that in the breaking changes doc!

I have had a hard time finding this comment:
https://github.com/aspnet/EntityFrameworkCore/issues/17617#issuecomment-529162589

I believe this pattern of querying data is quite often. At least I used to it since EF 6. Adding AsNoTracking() in these cases doesn't make sense for me considering the pattern. I understand it's too late to re-consider but please describe that behavior in the breaking changes at least.