Installation instructions are out-of-date

[tommorris]

The installation instructions state:

Go will install to a directory named go. Change to the directory that will be its parent and make sure the go directory does not exist. Then check out the repository:

$ hg clone -u release https://code.google.com/p/go

Google Code is no more, Go is hosted on GitHub (here, and the source code is in a Git repo rather than a Mercurial repo.

(I know that this repo hasn't been updated in years, just thought I'd file this in case there suddenly is an interest in maintaining/updating it.)