Add locator support to alphanumeric style

[Eloitor]

Fixes #48

[PgBiel]

Thanks!

Can you add a test like this one?

hayagriva/src/csl/mod.rs

Line 2996 in 0b32dca

fn test_alphanumeric_disambiguation() {

[PgBiel]

Is there a reason for the nested group with the same delimiter and this prefix? What is your intended output?

Of note, @citation[abc] produced [Cit25a, abc] in Typst 0.8.0, before the regression. We should probably stick to that.

[Eloitor]

what should be the output of @first[abc] @second[def]?

[Eloitor]

I attempted to add a test, but I don't know if it is possible (or necessary) to specify create a location in a BibliographyRequest...

       let finished = driver.finish(BibliographyRequest {
            style: &alphanumeric,
            locale: None,
            locale_files: &[],
        });