[clang-tools-extra] Add migration shell script to modernize-type-traits.rst (PR #202526)

[Baranov Victor via cfe-commits]

vbvictor wrote:

And what benefits does this check has over regular clang-tidy run with this check?
If you do `run-clang-tidy -p build/ -checks='-*,modernize-type-traits' -fix` you should get similar results at cost of roughly 1 compilation

https://github.com/llvm/llvm-project/pull/202526