[clang] [NFC][Clang][Headers] Update refs to ACLE in comments (PR #66662)

[David Spickett via cfe-commits]

https://github.com/DavidSpickett commented:

If these section refs weren't already here I'd suggest not adding numbers at all given that they will change later, and Firefox and Chrome seem hopeless at searching for them in the HTML document.

But we have them already so I won't suggest that :) Thanks for taking the time to do this.

https://github.com/llvm/llvm-project/pull/66662