markup/asciidoc: Add support for .TableOfContents

[npiganeau]

Fill the .TableOfContents template variable when writing Asciidoc content.
This is done by letting Asciidoc render its TOC as HTML, then extract this
HTML rendered TOC, parse it into a tableofcontents.Root and finally remove
it from the HTML content.
This aims to stay in the logic that the Asciidoc parsing is entirely done
by the external helper.

See #1687

[rustysys-dev]

@npiganeau I have no clue if I am authorized to approve anything or not.. Ill try the button, but that being said, I reviewed your PR and lgtm.

you need to fix the conflicting go.sum file though

[npiganeau]

@rustysys-dev Thanks for your review. I've just fixed the conflicts in go.sum.

[rustysys-dev]

@bep I apologize if mentioning you on this PR discouraged (please let me know if it is)

That being said, I wanted to bring the Hugo teams attention to this PR as it fixes a feature that is broken for asciidoc, and is important for my team and I.

I checked the code, and the logic follows through, is formatted correctly, and has tests and documentation. If you have some time to approve/merge/comment, we would all appreciate it.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. The resources of the Hugo team are limited, and so we are asking for your help.
If this is a bug and you can still reproduce this error on the master branch, please reply with all of the information you have about it in order to keep the issue open.
If this is a feature request, and you feel that it is still relevant and valuable, please tell us why.
This issue will automatically be closed in the near future if no further activity occurs. Thank you for all your contributions.

[forestsword]

Not stale. @rustysys-dev any way to move this fix along aside from @npiganeau rebasing?

[rustysys-dev]

@forestsword As you said, aside from @npiganeau re-basing we cannot do anything with this unless someone who has merge permissions decides to take a look at this. Once the re-basing is complete then we can try to get the attention of someone in charge again.

that being said, the fact that these specific files are conflicting means that someone may have fixed this elsewhere.

[forestsword]

It wasn't fixed. That file was just moved to the new markdown/asciidocext. @npiganeau are you still interested in this, I can do a rebase with your code if you'd like and open a new PR.

[bep]

If this looks good to the Asciidoc users in here, I'll happilly merge (once rebased).

[npiganeau]

Rebase is done

[bep]

@muenchhausen

[forestsword]

LGTM working as expected.

[muenchhausen]

@muenchhausen

I will try it out in the weekend.

[muenchhausen]

I was successfully able to run your changes.

Do you have a sample repo with an adoc file and a theme that uses .TableOfContents? I would like to see it.
We can also extend my sample repo hugo_asciidoc_ddd.

I found a small issue: Please correct your documentation and add empty lines between the headers. There is also a missing blank between :toclevels: and 4. Otherwise AsciiDoc won't be rendered correctly.

[npiganeau]

Documentation is corrected.

See muenchhausen/hugo_asciidoc_ddd#2 for a sample with TOC extraction to .TableOfContent.

[muenchhausen]

@npiganeau your changes work fine, thanks a lot! @bep I propose to merge.

[github-actions]

This pull request has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.