Ludovic noticed that the link to Emacs-Guix manual on this page:

  https://www.gnu.org/software/guix/manual/html_node/Package-Management.html

points to 404.  Although the according link in "one page" Guix manual:

  https://www.gnu.org/software/guix/manual/guix.html

is OK.  I think the attached patch should fix it.  But I'm not sure
anymore :-)