Add link to Haskell implementation

[fuzzypixelz]

I started working on this following A Hacker News post, so about a month ago. I believe Hustle still needs more testing to
be actually useful, so I'm hoping people can point to issues if they start playing around with it. This is not the Go nor the C
implementation you guys have been waiting for, however.

[zkat]

Whoa thank you! And no worries, I'm super happy with any implementation that comes along :))

[zkat]

Do you want to do a PR to the website as well, to add it there, too? https://github.com/kdl-org/kdl-org.github.io