-preview switches

[Adam D. Ruppe]

On Wednesday, 1 April 2020 at 17:51:47 UTC, Steven Schveighoffer 
wrote:
>> The way the documentation generator works at the moment is 
>> less than ideal.
>
> I don't know how to fix this.

This is why I abandoned the approach of using dmd entirely and 
wrote a separate doc generator with a separate parser.

Then it is able to display version things like here:

http://dpldocs.info/experimental-docs/arsd.simpledisplay.PosixFdReader.html

vs

http://dpldocs.info/experimental-docs/arsd.simpledisplay.WindowsHandleReader.html

It just plain tells you it is `version(Windows) class 
WindowsHandleReader`.