go.blog: fix links in "Introducing Gofix"
go.blog: fix links in "Introducing Gofix"

Fixes golang/go#8692.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/141420043

jeffreyliguori/blog,gorakhargosh/blog,gorakhargosh/blog