[clang] [clang] Finalize #embed support for C++26 (P1967R14) (PR #233285)

[Vlad Serebrennikov via cfe-commits]

Endilll wrote:

> That being said, any difference would be a bug so I'd be inclined to go ahead with this.

Bug on whose side? And what are we going to do with intentional differences, like [CWG3013](https://cplusplus.github.io/CWG/issues/3013.html)?

https://github.com/llvm/llvm-project/pull/233285