Update OpenZFS repository URL to version 2-8

[LeWimbes]

This PR updates the OpenZFS installation instructions to use the zfs-release-2-8 repository URL instead of zfs-release-2-2.

Changes

• Updated OpenZFS repository installation command from zfs-release-2-2 to zfs-release-2-8
• Removed version-specific references from section headings

References

• OpenZFS Documentation - RHEL-based distro
• OpenZFS Issue #17452

Testing

Verified successful installation of ZFS DKMS modules 2.2.8-1 in a VM on:

• Rocky Linux 8.10
• Rocky Linux 9.6
• Rocky Linux 10.0

Author checklist (Completed by original Author)

• Good fit for the Rocky Linux project? Title and Author Metatags inserted ?
• If applicable, steps and instructions have been tested to work
• Initial self-review to fix basic typos and grammar completed

Rocky Documentation checklist (Completed by Rocky team)

• 1st Pass (Document is good fit for project and author checklist completed)
• 2nd Pass (Technical Review - check for technical correctness)
• 3rd Pass (Detailed Editorial Review and Peer Review)
• Final approval (Final Review)

[sspencerwire]

Hey @LeWimbes Thank you very much for this. It's very valuable. One problem though, we can only adjust the English (source) language in a PR here. Our Crowdin translation engine gets confused when changes are made outside of that environment. What happens is that if the source language file is updated, the translators will see the change in the Crowdin interface and then do the appropriate translating. Can you edit your PR and remove the non-English language changes? If you can, then I'll get this merged. Thank you again!

[github-actions]

Test results for 08dcc58:

Number of broken URLs: 5

URL,RESULT,FILENAME
 http://your_ip,failed,guides/cms/mediawiki.md
 http://$(hostname):8080,failed,guides/repositories/pulp_fetch_upload.md
 https://ftp.gnu.org/gnu/tar/,failed,guides/backup/tar.md
 https://ftp.gnu.org/gnu/hello/hello-2.12.tar.gz,failed,labs/systems_administration_I/lab7-software_management.md
 https://repocompare.rockylinux.org,failed,release_notes/8_5.md

[LeWimbes]

Thanks a lot for the explanation @sspencerwire.
I've updated my previous commit to only include the changes for the two English installation instruction files.
Let me know if there's anything else you'd like me to adjust.

[sspencerwire]

Thanks for doing that @LeWimbes

[sspencerwire]

@all-contributors add @LeWimbes for content

[allcontributors]

@sspencerwire

I've put up a pull request to add @LeWimbes! 🎉