[clang] [-Wunsafe-buffer-usage] Add absl::{Span,string_view} to UnsafeBufferUsage analysis (PR #127698)

[Ilya Biryukov via cfe-commits]

https://github.com/ilya-biryukov requested changes to this pull request.

This makes sense, although I suspect it doesn't work because the code checks for `std` namespace.

It would be nice to get a signal from the code owners that they're happy with adding Abseil as a special case in  addition to STL. Hopefully it's a no-brainer as it's coming from Googlers, who are owners of Abseil.

Could you also add a test? (search for `Wunsafe-buffer-usage` inside `clang/test` if you need existing examples)

https://github.com/llvm/llvm-project/pull/127698