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

[David Spickett via llvm-commits]

DavidSpickett wrote:

@paschalis-mpeis these are the commands I was using earlier.

I doubt that this is 100% always going to be correct, so that's why I've said "modified" not "processed". I assume the amount and type of extra sections depends on the input binary too, so that's "may" have not "will" have.

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