Typst writer: A footnote should be able to be referenced multiple times

[YDX-2147483647]

Explain the problem.

If a footnote is referenced multiple times, it should be created only once, but the current implementation creates a new one for each reference.

By giving a label to a footnote, you can have multiple references to it.
—Footnote Function – Typst Documentation

Here is a footnote reference,[^1] and again.[^1]

[^1]: Here is the footnote.

pandoc --from markdown --to typst --no-highlight

Current output:

Here is a footnote reference,#footnote[Here is the footnote.] and
again.#footnote[Here is the footnote.]

Expected output:

Here is a footnote reference,#footnote[Here is the footnote.] <fn-1> and
again.@fn-1

Pandoc version?

• pandoc version 3.6.3
• Windows and https://pandoc.org/try/

Relates-to: #8893

[jgm]

This is essentially #1603.

Once the markdown is parsed, the Pandoc structure does not allow us to distinguish between the case where there was just a single note marker used and the case where multiple note markers are used. We just have an inline element Notes [Block].

[jgm]

Changing this would require changing the Pandoc structure to have either

• a block element Note Text [Block] and an inline element NoteRef Text, or less disruptively
• an inline element Note Text [Block] where the Text part stores the marker.

Of course, any change to Pandoc is a breaking change through the whole ecosystem and requires code changes virtually everywhere. So this wouldn't be a simple fix.