go-tour: remove built-in types from syntax highlighting keywords list
go-tour: remove built-in types from syntax highlighting keywords list

Fixes issue 40.

R=adg
CC=golang-dev
https://codereview.appspot.com/12975043

Committer: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>

golang-tr/go-tour-tr,golang-tr/go-tour-tr