feature: Display footnote content on <S-k>

[ricka-hunt]

Is your feature request related to a problem? Please describe.

I write a lot of prose in markdown, and I use footnotes for editorial comments. I find it frustrating to jump to the bottom of the screen every time I'd like to read a footnote.

Describe the solution you'd like

I would really enjoy a hover provider capability in the render-markdown LSP. using while hovering over a footnote marker to display the footnote definition in a floating window.

Describe alternatives you've considered

Currently I'm using the Markdown-Oxide LSP for this feature, (marksman can also do this), though I find that running a whole extra LSP just for this one feature is wasteful and bothersome.

Additional information

Thanks again for making this plugin, it's by far the most important one to my workflow <3