New References Macro

and even though the idea is nice, in practice it didn't end up anywhere.

I think it did: https://extensions.xwiki.org/xwiki/bin/view/Extension/References

I don't think the fact that the issue is not active is a valid reason for closing it. We should close issues as "won't fix" only if we don't think it should be implemented in XWiki (it could be implemented as a contrib extension). So what we need to validate here is the missing feature of the existing footnote macro, and whether we want to improve it or not.