Lechee check on PR is checking whole portal, instead of just modified content

[georgik]

The check should be localized only to added content, because otherwise the merge might fail in case of malfunction of url in unrelated content.

[f-hollow]

#107 limits link checking by pr-check-links to the PR diffs only.

[f-hollow]

There were numerous false positives in recent PRs.

Analyzing false positives yielded the following results:

• #149 and #167
  • Dump links from the commit after which the feature branch was created (as opposed to checking out current main and dumping the links)
• #164
  • Mimicking the pr-link-check workflow locally yielded false positives differing from the ones reported by GitHub Actions.
  • Among the mentioned false positives, the link https://docs.google.com/forms/d/e/1FAIpQLSeqeP4L90wLu0om38q-wvxKYKI1_Y4Hf4T928NQI8LBW4mHhQ/viewform?embedded=true was present in .lycheeignore, yet it still triggered false positives, escaping the question mark ...\?embedded... solved the problem.
  • Mimicking the pr-link-check workflow outside of the company network didn't yield any false positives!
  • While mimicking false positives in this and other PRs, I eventually discovered that lychee dumps only part of links at times (some files are skipped?). lychee's Troubleshooting section suggests "breaking the check into multiple lychee runs with different exclusion/inclusion rules". It might help resolve such false positives.

Actions required:

• Update the pr-link-check workflow to have the links dumped from the commit after which the feature branch was created

  git checkout -b <feature-branch>-main
  git reset --hard HEAD (discard all feature branch commits)
  dump all links using lychee