Add gitea slugification

[rodolpheh]

When generating TOC, the links are not properly slugified for Gitea. One of the issues I had was that Gitea expect all underscores to be hyphen.

This is a quick hack, I'm still missing the source for the slugification function of Gitea so I'm not sure all the proper changes are made when slugifying. Also the tests probably doesn't cover every cases.

[yzhang-gh]

Thanks for the PR.

I'm okay with this as you already implemented it. As for the failed test, you can make a document
containing heading # foo & < >  "foo" and see what anchor Gitea will generate.

[rodolpheh]

Sorry for the forced push, I was trying to hide my mistakes... Anyway, the tests are shown as not okay, but I tried triggering them on my repository and everything is okay. I don't know if you can run them again.

[rodolpheh]

Mmh the tests keep failing on this repository. See the pull request on my fork : https://github.com/rodolpheh/vscode-markdown/pull/4

[yzhang-gh]

Well, that's strange. Let me just merge it in.

[yzhang-gh]

All set. 🍻

[rodolpheh]

For future references, I think that gitea uses blackfriday for parsing and sanitizing the markdown, here is an explanation of the algorithm used for anchor sanitation in blackfriday.

[Lemmingh]

Gitea has migrated to goldmark with their own slugify method since version 1.11 released on 2020-02-10.

• https://docs.gitea.io/en-us/faq/#why-is-my-markdown-broken

  goldmark for Markdown rendering

• https://pkg.go.dev/code.gitea.io/gitea/modules/markup/markdown?tab=imports

• Change markdown rendering from blackfriday to goldmark  go-gitea/gitea#9533

• https://github.com/yuin/goldmark/blob/bd58441cc141c6455d2ed592a4f1d01adee4211a/README.md#context-options

  IDs allows you to change logics that are related to element id (ex: Auto heading id generation).

• Extended unicode characters discarded from auto heading IDs yuin/goldmark#56 (comment)

---

I hope the info above is useful to you.

[yzhang-gh]

Gitea has migrated to goldmark with their own slugify method since version 1.11 released on 2020-02-10.

👍. Just to leave a reminder for myself here, Hugo also uses goldmark (#689 (comment)).

[rodolpheh]

Woah this is great information, thank you very much. For now, I have improved the gitea slugification to follow more closely the blackfriday algorithm (see #764). It seems to work with a few exotic values and hopefully will work for most of the cases.

[rodolpheh]

For reference and if I'm not mistaken, this is the default goldmark function called for generating the IDs :
https://github.com/yuin/goldmark/blob/master/util/util.go#L517