LinkChecker validation inconsistent between Markdown and HTML

[ChrisZYJ]

#669 fixes a broken link by changing running.md#restarting-cases to md_running.html#restarting_cases. However, this change fails the CI test "LinkChecker / markdown-link-check (push)". Additionally, the LinkChecker appears to incorrectly validate links like references.md#Toro13, marking them as valid despite leading to non-existent pages (this applies to all reference links).

Maybe the LinkChecker works properly with Markdown files but doesn't correctly validate links in the Doxygen-generated HTML files.

[sbryngelson]

This seems to be the case. We may need to tell the linkchecker to ignore these files or find another way around it. It would be good to know if the documentation has dead links.

[sbryngelson]

I think the solution is to build the full documentation via ./mfc.sh build -t documentation and then check the files in CI for broken links.