[clang] [llvm] Enable unnecessary-virtual-specifier by default (PR #133265)

[Devon Loehr via llvm-commits]

DKLoehr wrote:

Ah, missed that, sorry. It seems there hasn't been a release since the warning was added, and the existing release note seems to still apply: https://github.com/llvm/llvm-project/blob/8bdcd0a96e65557c8c3bf506d186c49002db6463/clang/docs/ReleaseNotes.rst?plain=1#L291

https://github.com/llvm/llvm-project/pull/133265