[llvm] [BOLT][docs] Document commands to identify BOLT-ed binaries (PR #171458)

[Paschalis Mpeis via llvm-commits]

https://github.com/paschalis-mpeis approved this pull request.

Thanks for improving our docs, David. The placement looks good to me.

Let's give it a day in case Meta has any further suggestions.

https://github.com/llvm/llvm-project/pull/171458