[x/tour] go-tour: minor HTML/link error fixes         Fix issue 3421 for the go project.
[x/tour] go-tour: minor HTML/link error fixes
        Fix issue 3421 for the go project.

R=golang-dev, adg, r
CC=golang-dev
https://golang.org/cl/5946048
X-Tour-Commit: 1553c4643e18c8877eedc6db0e411c78b2793161

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website