[clang] #101784 part 1: introduce ctyped in an independent manner (PR #101941)

[Vlad Serebrennikov via cfe-commits]

https://github.com/Endilll commented:

Thank you for splitting that large PR into something smaller. That said, 1.6k lines of changes is no small change either.
This PR needs more high-level explanation of what you try to achieve and how. At the moment I'm not sold we want to go in this direction.

https://github.com/llvm/llvm-project/pull/101941