[clang-tools-extra] [clang-tidy] Improved readability redundant casting with enums (PR #111424)

[Félix-Antoine Constantin via cfe-commits]

felix642 wrote:

> +- some people may want to control this behavior and keep the explicit cast for enums, WDYT?

I can see why some people might want to explicitly cast the enum to its underlying type.
I could add the option `WarnEnumCastToUnderlyingType` which could default to `true`.

https://github.com/llvm/llvm-project/pull/111424