[clang] [Clang] Add __ugly__ spelling for the msvc attribute scope (PR #113765)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

In principle, I'm not opposed, but if cl.exe doesn't support the syntax for their vendor string, I don't know that we should support it ourselves. The signal of support from @StephanTLavavej is definitely a point in favor of going this route, but I'd feel most comfortable if we were following cl's lead rather than going off on our own.

https://github.com/llvm/llvm-project/pull/113765