Move Test URL check to Vitest

[fregante]

• Completes Improve feature verification #7132 (comment)
• Blocked by 🏓 Help add test URLs to the last features #7656

[fregante]

It would be nice to still output this positive annotation on all files though, just to bring the test URLs to light when reviewing, but it seems it's already not working?

[fregante]

Oof, vitest looks so good 🥹 it groups errors by type and I can click each filename in the terminal to reach them.

[fregante]

I need to restore this message too, to help user document new features. The message needs to be updated.

[fregante]

Current output, waiting for:

• 🏓 Help add test URLs to the last features #7656

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Tests 21 ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯

 FAIL  build/features.test.ts > features > center-reactions-popup.css
 FAIL  build/features.test.ts > features > clean-conversations.css
 FAIL  build/features.test.ts > features > clean-notifications.css
 FAIL  build/features.test.ts > features > github-bugs.css
 FAIL  build/features.test.ts > features > repo-stats-spacing.css
 FAIL  build/features.test.ts > features > safer-destructive-actions.css
AssertionError: Should have test URLs
 ❯ validateCss build/features.test.ts:109:3
    107|   );
    108| 
    109|   assert(/test url/i.test(file.contents().toString()), 'Should have test URLs');
       |   ^
    110|   return;
    111|  }
 ❯ build/features.test.ts:199:4

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/21]⎯

 FAIL  build/features.test.ts > features > command-palette-navigation-shortcuts.tsx
 FAIL  build/features.test.ts > features > comment-fields-keyboard-shortcuts.tsx
 FAIL  build/features.test.ts > features > convert-pr-to-draft-improvements.tsx
 FAIL  build/features.test.ts > features > cross-deleted-pr-branches.tsx
 FAIL  build/features.test.ts > features > emphasize-draft-pr-label.tsx
 FAIL  build/features.test.ts > features > esc-to-cancel.tsx
 FAIL  build/features.test.ts > features > esc-to-deselect-line.tsx
 FAIL  build/features.test.ts > features > hide-newsfeed-noise.tsx
 FAIL  build/features.test.ts > features > html-preview-link.tsx
 FAIL  build/features.test.ts > features > improve-shortcut-help.tsx
 FAIL  build/features.test.ts > features > linkify-labels-on-dashboard.tsx
 FAIL  build/features.test.ts > features > one-key-formatting.tsx
 FAIL  build/features.test.ts > features > patch-diff-links.tsx
 FAIL  build/features.test.ts > features > prevent-duplicate-pr-submission.tsx
 FAIL  build/features.test.ts > features > prevent-pr-merge-panel-opening.tsx
AssertionError: Should have test URLs
 ❯ validateTsx build/features.test.ts:162:2
    160|  );
    161| 
    162|  assert(/test url/i.test(file.contents().toString()), 'Should have test URLs');
       |  ^
    163| 
    164|  if (file.contents().includes('.addCssFeature')) {
 ❯ build/features.test.ts:204:4

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[2/21]⎯