chore: update some links to fred

[bsmth]

Description

Pointing to fred repo for frontend issues / developing.

Motivation

https://developer.mozilla.org/en-US/blog/launching-new-front-end/

[github-actions]

Preview URLs

• /en-US/docs/MDN/Community/Getting_started
• /en-US/docs/MDN/Community/Issues
• /en-US/docs/MDN/Community/Our_repositories

[chrisdavidmills]

@bsmth these changes look fine to me, so approving. As an FYI, I did a grep for the old yari URL across the repo, and found these additional instances:

files/en-us/mdn/kitchensink/index.md:> Don't delete this page. It's used by [mdn/yari](https://github.com/mdn/yari) for its automation.
files/en-us/mdn/writing_guidelines/howto/markdown_in_mdn/index.md:- <https://github.com/mdn/yari/pull/7017>
files/en-us/mdn/writing_guidelines/page_structures/sidebars/index.md:> See [Yari's CLI Tool](https://github.com/mdn/yari/blob/main/docs/cli-tool.md) documentation for information.

Do any of these need updating, while you are at it?

[bsmth]

Thank you!

Do any of these need updating, while you are at it?

I think these are okay, will ask eng for a look 👀

[caugner]

I think these are okay, will ask eng for a look 👀

Yes, I think those are okay, although we might want to write up something similar to Yari's CLI Tool docs for Rari's CLI Tools.