This PR updates our internal tool `conechokey` to use `ReadConsoleInputW` by default. It also adds a flag `-a` to force it to use `ReadConsoleInputA`.
I discovered this while digging around for #1503, but figured I'd get this checked in now while I'm still investigating.
Since this is just a helper tool, I spent as little effort writing this change - yea the whole tool could benefit from cleaner code but _ain't nobody got time for that_.