Markdown writer renders footnotes in figure captions under the figure

[cprecioso]

When implicit_figures is enabled and you're rendering to -t markdown_strict or -t markdown_mmd, if the figure caption has a footnote, it gets rendered under the figure itself and not with the rest of the footnotes at the end of the document.

Repro in pandoc 2.5

Posted in a new issue from #5121 as per #5121 (comment)

[cprecioso]

I did a bit of research. As I see it, there can be two possible kind of outputs. I'll be comparing them on Babelmark to see which markdown renderers handle them correctly. For reference, I can see that only pandoc (not in strict mode), PHP Markdown Extra, Maruku, MultiMarkdown, kramdown and mistune handle footnotes at all.

Option A: (only pandoc and MultiMarkdown 6 handle it correctly, and mistune does not support the embedded figure HTML at all - it's escaped)

Paragraph 1

<figure>
<img src="./my-figure.jpg" alt="My caption " width="50" /><figcaption>

My caption[^1]

</figcaption>
</figure>

Paragraph 2[^2]

[^1]: footnote in the caption

[^2]: footnote in a paragraph

Option B: (only pandoc handles it - also tried with some variations with newlines in case it made a difference (1, 2))

Paragraph 1

<figure>
<img src="./my-figure.jpg" alt="My caption " width="50" />
<figcaption>My caption[^1]</figcaption>
</figure>

Paragraph 2[^2]

[^1]: footnote in the caption

[^2]: footnote in a paragraph

[cprecioso]

I think the current approach is just ok for most markdown variants except two.

Maybe in -t markdown_mmd, the writer could output Option A, as MultiMarkdown handles that just fine.

And in -t markdown_strict, which is not expected to handle footnotes, the output should be in tune with the rest of the footnotes, like:

Paragraph 1

<figure>
<img src="./my-figure.jpg" alt="My caption " width="50" /><figcaption>My caption [1]</figcaption>
</figure>

Paragraph 2 [2]

[1] footnote in the caption

[2] footnote in a paragraph