[clang] [CIR][docs] C++ cleanup and exception handling design for CIR (PR #177625)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic commented:

This looks like you could end up with extreme levels of nesting of cir.cleanup.scope.  Which isn't necessarily an issue, but you could easily trigger a stack overflow if you recursively walk the IR.

https://github.com/llvm/llvm-project/pull/177625