Link checker must check external links

[ashishguptaiitb]

In the Dashboard settings, the UI mentions Automatically check your docs for broken links. This gave me the wrong impression that all links will be checked. But only internal ones are checked. Checking all links in GitHub PR will be useful to help us keep our docs free of broken links to third-party websites.

Till then, I'd request that the UI caption be updated. It is correctly in the docs, but not highlighted, so I missed it.

It is misleading since it says "link-rot Succeeded" in the GitHub PR, however, a third-party link checker reported multiple genuine issues with external links, such as multiple redirects and 404s. Link rot's logic must extend to all links.