Link the source

[Adam D. Ruppe]

I added automatic source linking to my "improveddoc" program.

http://arsdnet.net/d-web-site/std_stdio.html (see the link on the right)

If this reaches the point where it is good enough for the official
site, we'll have it there too.

It needs to know the commit ID of the release to link to the file.
This way, you are looking at the same source you are reading the
documentation for, to avoid version confusion.