docs: replace broken links in ramfs-rootfs-initramfs docs

docs: replace broken links in ramfs-rootfs-initramfs docs

http://www.uwsg.iu.edu/ doesn't seem to exist anymore.
I managed to find backups on archive.org, which helped me find
the right links on https://lore.kernel.org/.

http://freecode.com/projects/afio was also down, so I figured
it could be replaced with https://linux.die.net/man/1/afio.

Replace broken links to mailing list and aifo tool.

Signed-off-by: Nadav Tasher <tashernadav@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251025171625.33197-1-tashernadav@gmail.com>