[llvm] [ADT] Add DenseSet(llvm::from_t, Range) (PR #131832)

[Jakub Kuderski via llvm-commits]

https://github.com/kuhar commented:

> while forward-porting std::from_range from c++23.

Could you describe (or link to) what `std::from_range` is and explain why we'd want to use it in llvm?

https://github.com/llvm/llvm-project/pull/131832