Create a warning for OpenSUSE and NixOS due to low package availability

But Fedora DOES have a warning for being less up to date than other recommended distros, > Fedora has a semi-rolling release cycle. While some packages like the desktop environment are frozen until the next Fedora release, most packages (including the kernel) are updated frequently throughout the lifespan of the release. Each Fedora release is supported for one year, with a new version released every 6 months. And Arch has the AUR, which none of the other distros have.