[libcxx] [clang-tools-extra] [llvm] [clang] [libcxx] adds ranges::fold_left_with_iter and ranges::fold_left (PR #75259)

[Christopher Di Bella via cfe-commits]

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@@ -89,9 +89,7 @@ struct __fold_left_with_iter {
   }
 };
 
-inline namespace __cpo {
 inline constexpr auto fold_left_with_iter = __fold_left_with_iter();
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cjdb wrote:

I've updated the description in this PR, which I _think_ becomes the main message for a squash-and-merge.

https://github.com/llvm/llvm-project/pull/75259