Tag packages with languages used

This is not fully though through. But github has a feature where it shows which language a repositories is written in..

It might be nice to have the analysis of a package. Just look for `*.dart|py|java|kt|kts|m|mm|M|h|c|cc|cpp|swift|js` and show percentages maybe?

This would be useful insights for flutter packages. See https://github.com/dart-lang/pub-dartlang-dart/issues/187#issuecomment-477161797. I'm not sure searching is useful, but maybe...