[clang] [clang][Docs] Document X86 interrupt attribute (PR #65662)

[Phoebe Wang via cfe-commits]

https://github.com/phoebewang approved this pull request.

LGTM. I didn't review Clang document before, but I'll give approval since I don't find anything blocking it.

https://github.com/llvm/llvm-project/pull/65662