[llvm] [ADT] Add SmallVectorImpl::append_range (PR #93384)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

> Don't we already have (the more generic) `append_range(V, R)` for this purpose?

Yes, the aim is to convert those calls to `llvm::append_range` on `llvm::SmallVector` to `llvm::SmallVector::append_range`.  Once we switch to C++23 in a few years, we can convert those calls to `llvm::append_range` on `std::vector` to `std::vector::append_range` also.

https://github.com/llvm/llvm-project/pull/93384