[clang] Introduce paged vector (PR #66430)

[Chuanqi Xu via cfe-commits]

ChuanqiXu9 wrote:

Sorry. I meant to sent: https://llvm.org/docs/ProgrammersManual.html#picking-the-right-data-structure-for-a-task. Also I feel like the comments are much less than other ADT types. I mean these are important and fundamental data structures. So that almost every LLVM developer need to learn them someday. And it would be pretty helpful to see the explanations. You can see other the implementation of other ADTs for example.

https://github.com/llvm/llvm-project/pull/66430