Add support for footnotes

[djui]

redcarpet has with tables, code fence blocks, and many other extensions seems to lack footnote support to complete a set of features kramdown and maruku provide.

[robin850]

Hello,

This seems legit since footnotes are in markdown specs. We should implement it! Thanks for this proposal @djui.

[aprescott]

I don't think the footnotes being requested are the same as the reference links mentioned in the spec. (They should already be in Redcarpet.) Rather, it's actual rendered footnotes in the HTML, like those that PHP Markdown Extra supports.

[djui]

@aprescott correct. After some issue crawling in sundown I actually found that this is already requested quite heavily but @vmg wanted to put it on hold (or allow pull requests) as they were working on a standardized markdown specification.

Meanwhile I found fork that implements footnotes and merged that into my redcarpet fork to get it uptodate. It works for me (and was reported to work for many other). However, the decision to progress and integrate this, is up to the core developers, like you guys, @robin850?

[robin850]

I don't think the footnotes being requested are the same as the reference links mentioned in the spec. (They should already be in Redcarpet.) Rather, it's actual rendered footnotes in the HTML, like those that PHP Markdown Extra supports.

Ah, right. I read it too quickly!

@djui : I'm personnaly 👍 with this. I'm most of the time in favor of such improvements (especially when they are still implemented ).

@mattr- : thoughts on this please?

[mattr-]

I want to see a pull request. 😄

[djui]

There you go: #241

[robin850]

Finally, #271 has been merged. We can close this. Thanks everyone!