Update pygi docs

[infirit <infirit gmail com>]

Hi,

git.gnome.org for Gtk forwards the request to gitlab automatically but
the line number is not working because it is handled differently. So
source links in the docs work but don't move to the correct line number.

I saw pgi-docgen got updated already so it would be nice if the web and
devhelp repo can be updated?

Thx
~infirit