[clang-tools-extra] [clang-tidy] add misc-constexpr check (PR #146553)

[Denis Mikhailov via cfe-commits]

denzor200 wrote:

`constexpr` is one of the important additions of C++11. Most of the users will search this check in "modernize" section and will be misled by not finding it there.
"misc-const-correctness" - not a modernize check at all, it even relevant for C++98, so it exists in "misc"


https://github.com/llvm/llvm-project/pull/146553