footnotes should use semantic markup

[anarcat]

It seems that multimarkdown does not use standard semantic markup for footnote references. e.g. this piece of code:

#!/usr/bin/perl -w

use Text::Markdown::Discount;
use Text::MultiMarkdown;
my $text = <<EOF;
Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec hendrerit tempor tellus. Donec pretium posuere tellus. Proin quam nisl, tincidunt et, mattis eget, convallis nec, purus.[^f]

[^f]: this is a footnote

EOF
my $html = Text::MultiMarkdown::markdown($text);
print $html;
$html = Text::Markdown::Discount::markdown($text, Text::Markdown::Discount::MKD_EXTRA_FOOTNOTE());
print $html;

outputs this:

<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec hendrerit tempor tellus. Donec pretium posuere tellus. Proin quam nisl, tincidunt et, mattis eget, convallis nec, purus.<a href="#fn:f" id="fnref:f" class="footnote">1</a></p>

<div class="footnotes">
<hr />
<ol>

<li id="fn:f"><p>this is a footnote<a href="#fnref:f" class="reversefootnote">&#160;&#8617;</a></p></li>

</ol>
</div>
<p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Donec hendrerit tempor tellus. Donec pretium posuere tellus. Proin quam nisl, tincidunt et, mattis eget, convallis nec, purus.<sup id="fnref:1"><a href="#fn:1" rel="footnote">1</a></sup></p>
<div class="footnotes">
<hr/>
<ol>
<li id="fn:1">
<p>this is a footnote<a href="#fnref:1" rev="footnote">&#8617;</a></p></li>
</ol>
</div>

Notice how Discount (correctly, IMHO) outputs the footnote reference within a <sup> tag to make sure the footnote is smaller and "in exponent".

Without a <sup> tag, I have to add custom elements to my stylesheet otherwise footnotes appear

a.footnote { vertical-align: super; font-size: xx-small; }

This is without the style:

And this is with the style:

If MMD would just output a supplementary <sup> here, things would look much better without any custom style. Out of the box, the footnotes don't really look nice at all, and in fact, confuse both regular and screen readers.