[clang] [clang][analyzer] CallAndMessage warnings at pointer to uninitialized struct (PR #164600)

[Donát Nagy via cfe-commits]

https://github.com/NagyDonat approved this pull request.

Thanks for the update! I really like the solution with the `format_provider` specialization, it is even more elegant than what I was suggesting.

I think this commit is ready to be merged. @steakhal Do you have anything to add?

https://github.com/llvm/llvm-project/pull/164600