Add missing reference to Kramdown.
Add missing reference to Kramdown.

amatsuda/haml,keithpitty/haml,haml/haml,dg1dd1ngs/haml,tangposmarvin/haml,haml/haml,uniba/hamldoc_ja,nazar-pc/haml,stanhu/haml,sideci-sample/sideci-sample-haml,macressler/haml,concord-consortium/haml,tangposmarvin/haml,dg1dd1ngs/haml,nazar-pc/haml,stanhu/haml,macressler/haml,keithpitty/haml,haml/haml,haml/haml