Alphanumerical citation style ignores supplement

[lynn]

From https://github.com/typst/typst/issues/1330.

CitationStyle::citation for Alphanumeric doesn't inspect atomic.supplement inside the for atomic in parts loop.

Maybe it simply needs something like:

+           if let Some(supplement) = atomic.supplement {
+              res += ", ";
+              res += supplement;
+           }
            items.push(res);

…but maybe it's more complicated than that.

[laurmaedje]

The alphanumeric CSL style doesn't have a citation-locator, which regressed this.

[IEncinas10]

Hello! I'm writing my thesis with typst and I would like to have this working.

I dont know how hard is to fix this issue because I'm unfamiliar with the codebase, but if is not too complicated I would appreciate a few pointers and give it a try.

Thanks!