bug#67986: Feature request: link git repo in download page.

[Russell Hernandez Ruiz]

The download page,
https://guix.gnu.org/en/download/
provides a source tarball, and at the bottom also there is an FTP
mirror.

A link to the guix git page would be nice:
https://git.savannah.gnu.org/cgit/guix.git/

Sincerely,
Russell