Feature request: footnotes

[grepsuzette]

Marked version:
marked v12.0.2

Describe the bug
"footnotes" seem unsupported.

To Reproduce
Having bottom-notes such¹ as² this³ kind⁴ will have them on a continuous line, missing some <br /> probably (edit: actually not a bug, it's currently unsupported!).

Demo is here

Commonmark does not have them either. It may just be a github thing.
Would you have it if PR?

Footnotes

1. in github ↩

2. those are rendered one ↩

3. per line, ↩

4. but not with markedjs (it's shown on one line). ↩

[UziTech]

Unfortunately GitHub still doesn't have footnotes in their spec which makes it very difficult to know how to handle edge cases.

There is already an extension that works to add them to marked: https://github.com/bent10/marked-extensions/tree/main/packages/footnote