Awesome: asserts turn into writeln for ddoc'd unit tests

[Steven Schveighoffer]

This is something I didn't realize happened (I remember discussing it a 
while back). Awesome work whoever did it, and works great!

To recap, for anyone like me who is clueless, for documented unit tests:

///
unittest
{
    int x = 5;
    assert(x == 5);
}

turns into this in ddoc:

int x = 5;
writeln(x); // 5

Very cool :)

A question: is this for all libraries, or is it a special case for 
dlang.org?

-Steve