docs: add big announcement notice for old major versions

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes Docs: link to docs for previous major versions, with the appropriate caveats #10483
• That issue was marked as accepting prs
• Steps in Contributing were taken

Overview

Relies on an CURRENT_MAJOR_VERSION env variable I've set in Netlify. You can preview it with a different version locally with:

CURRENT_MAJOR_VERSION=9001 yarn start

💖

[typescript-eslint]

Thanks for the PR, @JoshuaKGoldberg!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[netlify]

✅ Deploy Preview for typescript-eslint ready!

Name	Link
🔨 Latest commit	2e92aa3
🔍 Latest deploy log	https://app.netlify.com/sites/typescript-eslint/deploys/68221cc9fe9e20000967b48e
😎 Deploy Preview	https://deploy-preview-11178--typescript-eslint.netlify.app
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Lighthouse	1 paths audited Performance: 89 (🔴 down 10 from production) Accessibility: 100 (no change from production) Best Practices: 100 (no change from production) SEO: 98 (no change from production) PWA: 80 (no change from production) View the detailed breakdown and full score reports

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[nx-cloud]

View your CI Pipeline Execution ↗ for commit 2e92aa3.

Command	Status	Duration	Result
nx typecheck ast-spec	✅ Succeeded	<1s	View ↗
nx run-many --target=build --exclude website --...	✅ Succeeded	2s	View ↗
nx run-many --target=clean	✅ Succeeded	11s	View ↗

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☁️ Nx Cloud last updated this comment at 2025-05-14 20:05:17 UTC

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.92%. Comparing base (d5209cd) to head (2e92aa3).
Report is 16 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #11178   +/-   ##
=======================================
  Coverage   90.91%   90.92%           
=======================================
  Files         499      499           
  Lines       50809    50845   +36     
  Branches     8369     8384   +15     
=======================================
+ Hits        46195    46231   +36     
  Misses       4599     4599           
  Partials       15       15           

Flag	Coverage Δ
unittest	90.92% <ø> (+<0.01%)	⬆️

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see 3 files with indirect coverage changes

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