Adding Markdown to Ddoc

[Mike Parker]

On Wednesday, 6 December 2017 at 04:11:33 UTC, Walter Bright 
wrote:
> https://help.github.com/articles/basic-writing-and-formatting-syntax/
>
> Anyone interested in picking up the flag?
>
> (I know this has come up before, and I've been opposed to it, 
> but I've changed my mind.)

Can you see me jumping up and down over here? I don't care about 
it for source documentation, but if we could start using Mardkown 
in place of Ddoc macros for the web site, woohoo!