Conform styling of footnote

[mojavelinux]

The built-in HTML converter and Asciidoctor PDF do not display footnotes in the same way. And both differ from the style used on Wikipedia. I think we should consider coming up with a style on which to align.

Here are several proposals. (Ignore the underlines as those are being added by GitHub).

(A)

Text with footnote.^[1]

...

1. Footnote text.

It's kind of a blend of the Wikipedia style and the Chicago style.

Wikipedia uses a separate caret adjacent to the footnote number in the footnote list instead of making the number a link:

(B)

Text with footnote.^[1]

...

1. ^ Footnote text.

However, that looks a bit strange to me. Many style guides will show the footnote number in superscript without the dot. For example:

(C)

Text with footnote.^[1]

...

¹ Footnote text.

This raises the question as to whether the brackets are needed around the footnote in the text so that the styles match.

(D)

Text with footnote.¹

...

¹ Footnote text.

What I'm certain of is that almost no one using square brackets around the footnote number in the footnote list.

Whatever we decide, there still should be enough markup so that the appearance can be modified using CSS.

[someth2say]

My 5 cents:
(A) and (C) seems the sanest options to me.
I personally don´t like (B), but I see the reason behind using the caret (implying a back-navigation to the footnote).
(D) is prone to confusion, as the footnote can be misinterpreted as an exponent.

[mojavelinux]

I'm leaning towards (C) myself. Great point about (D).

[Larhzu]

I like that the above ideas make the brackets part of the link. It makes the link a larger target to hit.

Both (A) and (C) are good. I agree with someth2say about the problem with (D). If I was forced to choose between (A) and (C), I might choose (A) because I feel having the number in normal font size is fine in the footnote list. But I'm equally happy with (C).

If the same footnote is referenced from more than one location, Wikipedia links to each location in the footnote list using letters (the caret isn't a link then). Having back-references to all locations is nice but I don't have a strong opinion if Asciidoctor should do a similar thing. I just want to mention this detail to ensure that the inclusion or omission of the feature is an intentional choice instead of "oops no one thought about it". :-)

The default theme on Wikipedia uses superscript in bold and italic:

1. ^ ^{a b c} Footnote text.

Using letters might add some language-specific complexity. For example, Wikipedia uses an arrow instead of a caret and cyrillic letters in Ukrainian (I don't speak the language):

1. ↑ ^{а б в} Footnote text.

Using numbers might avoid the language-specific style. Also omitting the caret or arrow gets close to the (A) style:

(E)

1. ^{1 2 3} Footnote text with multiple references.
2. Footnote text with single reference.

I suppose that style works but it doesn't seem ideal. Using numbers for two purposes in the same context could be a little confusing. So letters could be nicer if the language-specific part isn't a problem. An example without bold:

(F)

1. ^{a b c} Footnote text with multiple references.
2. Footnote text with single reference.

With brackets the links are easier to hit but I guess it takes too much space and looks a bit weird:

(G)

1. ^{[a] [b] [c]} Footnote text with multiple references.
2. Footnote text with single reference.