[llvm] [Option] Use a range-based for loop (NFC) (PR #145446)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

> Can we move Values to use unique_ptr and delete the whole thing?

@arsenm I like the idea, but the interface here is complicated.  This class sometimes owns these strings, and sometimes it doesn't.  `OwnsValues` keeps track of the ownership.


https://github.com/llvm/llvm-project/pull/145446