add link checking to CI

[tylerauerbeck]

Add link-checking to CI

To ensure that all links stay up to date and valid, this PR adds lychee to check that there are no dead links within the repository

How to use

Open pull request, watch lychee run and check for dead links

Testing done

Ran this against the existing repository and added the appropriate ignore rules and addressed existing dead link.

[Describe the testing you have done before submitting this PR. Please include both the commands you issued as well as the output you got.]

• [X] Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• [X] Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.

[ervcz]

Hello @tylerauerbeck, great addition!

I see it checks a few file types by default. [default: md,mkd,mdx,mdown,mdwn,mkdn,mkdown,markdown,html,htm,txt] I was wondering if it would make sense to check jsx, tsx files too.

 - name: Check links
    uses: lycheeverse/lychee-action@82202e5e9c2f4ef1a55a3d02563e1cb6041e5332 # v2.4.1
    with:
      fail: true
      args: --extensions js,ts,jsx,tsx

I'm curious what would be the result including those filetypes too.

[tylerauerbeck]

Alright, this should be in good shape with all the extensions you mentioned. This will probably require a little tweaking as we play around with this a little more.

The only links that I needed to outright ignore or change were ones at code.google.com and x.com because they were intermittently returning 500 errors (code.google.com) or just always returning a 400 (x.com) but only from CI.