I made a few changes to the GoLexer. After looking at some go code that I had pushed to Github, I realized that things like bool, nil, and lots of newer builtins to the language were not supported. The only things missing now should be imaginary number literals and complex number literals -- I'm not familiar enough with regular expressions to implement them.
Also, I hope I didn't do anything incorrect in submitting this. This is my first time using Bitbucket and Mercurial.