[clang] [Sema] Propagate preferred_name attribute to existing specializations (PR #186741)

[Younan Zhang via cfe-commits]

https://github.com/zyn0217 commented:

Please make sure you have read the contribution guide regarding the AI use part before you move forward: https://llvm.org/docs/AIToolPolicy.html

Thanks.

https://github.com/llvm/llvm-project/pull/186741