Using Markdown with ReSpec should support footnotes (part of GFM)

[lokal-profil]

Is your feature request related to a problem? Please describe.
I want to use Github Flavored Markdown (GFM) which the documentation states that Respec supports, but Respec does not handle footnotes which ar part of GFM.

Today I need to replacing the footnote markdown by hand-crafting the equivalent html in the markdown file. This makes the markdown files more difficult to manage and increases the risk of broken links.

Describe the solution you'd like
To render footnotes (as supported by GFM) in the same visual manner as GitHub. They can either be in a separate end section or, at the end of the section including the md file.

Additional context
How Github visualises the footnotes can be seen here: footnotes

Describe any alternatives you've considered
If the conclusion is to not support footnotes then the documentation should be amended to clarify that respec does not support this aspect of GFM.

[lokal-profil]

Note that the spec published at https://github.github.com/gfm is not up to date and GFM now supports footnotes¹²

There is a markedjs extension which introduces support for GFM footnotes.

Footnotes

1. https://github.com/github/cmark-gfm/issues/236 ↩

2. https://github.blog/changelog/2021-09-30-footnotes-now-supported-in-markdown-fields/ ↩