New review comment by paper42 on void-packages repository

https://github.com/void-linux/void-packages/pull/32636#discussion_r694158641

Comment:
My first suggestion is to have gi-docgen **only** in hostmakedepends, we don't need it in makedepends. I think we should always go with gi-docgen if possible, because it's more modern, some projects drop gtkdoc and it produces prettier documentation.

The second comment is unrelated to documentation and also totally wrong (my bad). I thought they ship GTK GUI, but they just use python3-gobject. So ignore the second part and @ericonr's comment