Remove switch case fallthrough

[rempas]

On Thursday, 13 May 2021 at 16:48:36 UTC, Steven Schveighoffer 
wrote:
> First step is to make implicit fallthrough an error instead of 
> a deprecation. Then after a time, we might be able to make 
> break optional.
>
> -Steve

Exactly! I hope the community will think about it. Like I said, I 
don't think having some stuff like they are just to do it is a 
good thing for anyone.