Docs rawhide needs fixing

In rawhide there is outdated information:

https://docs.fedoraproject.org/en-US/fedora/rawhide/install-guide/ shows the withdrawn installation guide and some community members provide suggestions for improving it. We should definitely delete that.

https://docs.fedoraproject.org/en-US/fedora/rawhide/ shows the old introduction. The new text must show up here.