[Typing-sig] Re: Supporting dataclass-like semantics

Thanks for identifying those behavioral mismatches between attrs and dataclass. These differences are unfortunate, especially given that dataclass evolved from attrs.

I've updated the [Limitations](https://github.com/microsoft/pyright/blob/main/specs/dataclass_transforms.md...) section of the spec to capture these and other pieces of feedback so we can collectively decide which of these limitations need to be addressed (either in the dataclass_transform spec or in attrs) and which can potentially be ignored (because they are esoteric edge cases that impact very few uses in practice).

Keep the feedback coming!

-Eric