Add Hacker News discussion about Arch Linux migration to Open Source Program handbook

Why is this change being made?

💡 Provide a detailed answer to the question on why this change is being proposed, in accordance with our value of Transparency.

CHANGEME - add the details saying why, not just what.

ArchLinux bug tracker migration is completed, and discussed on Hacker News. A question about distributions using GitLab inspired me to reading the Open source program handbook, which has a Hacker News section at the bottom, documenting the impact.

This MR adds the Arch Linux discussion.

Author and Reviewer Checklist

Please verify the check list and ensure to tick them off before the MR is merged.

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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