[clang] [clang-tools-extra] [clang-tidy] Add new check `modernize-use-designated-initializers` (PR #80541)

[Danny Mösch via cfe-commits]

SimplyDanny wrote:

@PiotrZSL: I'm not quite sure if I reproduced all your suggested examples properly. Almost all of them appeared to be working as expected already, so I only added them as test cases.

https://github.com/llvm/llvm-project/pull/80541