[clang] [-Wunsafe-buffer-usage] Add a new warning for uses of std::span two-parameter constructors (PR #77148)

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https://github.com/jkorous-apple approved this pull request.

I will just say that I didn't imagine this warning to be made part of the analysis machine we use to produce fixits and it seems like at couple places the patch struggles with the abstractions the machine uses but overall I don't think it's completely unreasonable either and we can discuss a different structure later.

https://github.com/llvm/llvm-project/pull/77148