[llvm] [llvm-objcopy] Add llvm-objcopy option --set-symbol-visibility (PR #80872)

[Fangrui Song via llvm-commits]

https://github.com/MaskRay commented:

Since --set-symbols-visibility is added, it should be mentioned in the description (first comment) as well.

https://github.com/llvm/llvm-project/pull/80872