[clang] [clang][ASTMatcher] Add matchers for CXXFoldExpr (PR #71245)

[Julian Schmidt via cfe-commits]

5chmidti wrote:

> @5chmidti do you need us to merge that for you?

^^ coincidentally, I got access today. 

Given that the branch is from November, should I use the update branch feature beforehand, or do you think it's fine to merge it like this?

https://github.com/llvm/llvm-project/pull/71245