Fix typo in doc comments
Fix typo in doc comments

tangposmarvin/haml,nazar-pc/haml,haml/haml,haml/haml,dg1dd1ngs/haml,tangposmarvin/haml,nazar-pc/haml,keithpitty/haml,haml/haml,macressler/haml,stanhu/haml,dg1dd1ngs/haml,macressler/haml,keithpitty/haml,haml/haml,stanhu/haml