Migrate markdown-link-check action to maintained fork

[snazy]

Is your feature request related to a problem? Please describe.

Replace the gaurav-nelson/github-action-markdown-link-check, which is unmaintained since Apr 2025, with tcort/github-action-markdown-link-check, once apache/infrastructure-actions#368 is merged.

Describe the solution you'd like

No response

Describe alternatives you've considered

No response

Additional context

No response

[adam-christian-software]

One enhancement that we might want to consider while doing this is to handle the flaky failures when an external page cannot be reached. There have been a few times where the link check will fail when I tried to check in. I suppose we could either do some sort of retry or have some sort of exclude clause for external pages.

What do you think, @snazy ?