[clang] [NFC][clang] Quote literal builtin attribute markers in Builtins.def docs (PR #160080)

[Nikolas Klauser via cfe-commits]

philnik777 wrote:

> > and just left a 'link' to it here instead?
> 
> Also, is there a reason why we can’t just delete this file entirely and put the link e.g. in `Builtins.td`/`BuiltinsBase.td`

Since this isn't useful for the tablegen files I'm not sure that makes a ton of sense. Maybe rather put a comment in the `Builtins*.def` files that still exist?

https://github.com/llvm/llvm-project/pull/160080