generated links to pub.dev break due to stale doc removal... no warnings? #3543
Description
I added on to an existing issue regarding pub.dev's removal of non-current docs (dart-lang/pub-dev#6245 (comment)). Right now, that behavior causes a bad experience due to broken links in dart doc-generated docs.
Due to #3331, I can't tell whether or not the links broken due to out-of-date pubspec.lock dependencies are being caught by --validate-links.
Regardless, it would be helpful for dart doc to clearly warn about broken links to pub.dev docs.