`@:inheritDoc` doesn't work for typedef fields

Maybe can be implemented
```haxe
typedef Foo = {
/**
base doc
**/
var ?foo:Int;
}

typedef Bar = {
@:inheritDoc(Foo.foo)
var ?bar:Int;
}

class Main {
static function main() {
final foo:Foo = {
foo: 0
};
final bar:Bar = {
bar: 0 // no doc
};
}
}

```