Removed dead links to unwritten keyword docs
Removed dead links to unwritten keyword docs

Most of these will eventually be filled, but right now travis-ci enjoys
complaining about the fact that there's links that lead nowhere, so
they're gone. Hopefully someone remembers to re-add them later.

aidancully/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,GBGamer/rust,graydon/rust