Comment 1 for bug 1166653

http://www.pcworld.com/article/2033316/ubuntu-13-04-raring-ringtail-drops-wubi-in-final-beta.html
According to this article it is dropped for Raring.
Instead of removing the Wubi section from Installation chapter, perhaps we could mention that the description of Wubi is valid for previous versions of Ubuntu? Or is that confusing.