Releases: Link-only releases redirect to download page with error message

To reproduce, click on 'ppa' here: https://inkscape.org/en/release/0.92.1/gnulinux/

One way to solve this would be to display the link(s) on the donation page, and no error message, or to go to the link directly. We might need to differentiate between links and download files. Having two links for link-only release platforms is useful, as sometimes they need explanation about usage. For some (like snap), there can't be a link to the repo, only an explanation.