More operators inside `is(...)` expressions

[Ogi]

On Tuesday, 1 September 2020 at 14:00:19 UTC, Steven 
Schveighoffer wrote:
> But Walter is never going to approve any changes here, as this 
> is one area where he will not budge, due to past experience 
> with the C Preprocessor abuse. So this discussion is only 
> academic. Just use the workarounds and move on.

Whoever would do horrible deeds with `version` is still able to 
do all of them with `static if`, meanwhile the good guys are 
stuck with this wooden syntax. Seems a bit irrational to me.

I feel like beating a dead horse. Surely it has been discussed ad 
infinitum. And after all, it’s not such a big deal, it’s not like 
you have to juggle versions in your code all the time. But things 
like that are no good for D’s public image.