[clang] [clang][Sema] Add -Wswitch-default warning option (PR #73077)

[dong jianqiang via cfe-commits]

dongjianqiang2 wrote:

> There is one clang-tidy check (bugprone-switch-missing-default-case) also for this feature.

Thank you for your reply. It may be a more convenient and straightforward way if can be identified during compile time. 
On the other hand, it it more compatibile with GCC's hehavior. : )

https://github.com/llvm/llvm-project/pull/73077