GC/nogc status in docs

[Atila Neves]

On Tuesday, 14 July 2020 at 12:07:47 UTC, Adam D. Ruppe wrote:
> On Tuesday, 14 July 2020 at 12:03:30 UTC, Atila Neves wrote:
>> I mentored work on adding @nogc information to every function 
>> in Phobos. It's not done yet, but it's nearly there.
>
> Did you do it as @nogc unittests?

Yes.

> Doing it with the direct annotation would be overly limiting 
> due to lambdas etc.

I'm open to ideas on how to do it otherwise.