[clang] [clang] Implement provisional wording for CWG2398 regarding packs (PR #90820)

[Matheus Izvekov via cfe-commits]

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mizvekov wrote:

> Sounds like should perhaps note that we are implementing our own resolution, until there's an update to the cwg issue that can be referred to?

That could be. Is there another similar issue we could use as a reference on the format for this?

https://github.com/llvm/llvm-project/pull/90820