Deprecate std.signals?

[Berni44]

On Tuesday, 30 March 2021 at 11:23:21 UTC, Berni44 wrote:
> I've got the feeling, that std.signals is rarely used and not 
> up to D's standards... Therefore I suggest to move it to undead 
> and deprecate it.
>
> But I might err on this. What do you think?

I meanwhile filed a 
[PR](https://github.com/dlang/phobos/pull/7952). If you've got 
still any opinions on that, you might like to share them there.