[clang] [clang] Adds a RecursiveASTEnterExitVisitor data type (PR #136136)

[via cfe-commits]

https://github.com/Sirraide requested changes to this pull request.

I’m sorry, but without a *very* strong motivation and concrete use case for this, I’m going to NAK this addition: as a matter of fact, I’ve actively been working on *removing* uses of `RecursiveASTVisitor` in favour of `DynamicRecursiveASTVisitor` for a while now because of the former’s rather abysmal impact on both compile-times and binary size—the last thing we want, unless it it *absolutely necessary* for some reason, is add *another* CRTP-like recursive AST visitor.

https://github.com/llvm/llvm-project/pull/136136