[clang] [clang] Change style of superseded issues on C++ DR status page (PR #96051)

[via cfe-commits]

h-vetinari wrote:

I was wondering for a while along similar lines, if NAD ("not a defect") shouldn't get a downgraded colour as well. A "No" to  NAD is certainly less relevant than an actual defect report, isn't it?

https://github.com/llvm/llvm-project/pull/96051