Enable `Github Flavored Markdown` option in `pulldown-cmark`

Feature requests
1

I tried using blockquotes with GitHub-style tags and noticed that Zola doesn’t support this feature.

After looking at the pulldown-cmark source code, I saw that it already supports this feature, but it needs to be enabled with the pulldown_cmark::Options::ENABLE_GFM option in the parser.

From the pulldown-cmark docs:

        /// Misc GitHub Flavored Markdown features not supported in CommonMark.
        /// The following features are currently behind this tag:
        /// - Blockquote tags ([!NOTE], [!TIP], [!IMPORTANT], [!WARNING], [!CAUTION]).
        const ENABLE_GFM = 1 << 11;

This enables rendering like the following:

> [!NOTE]
> Note blockquote

to:

<blockquote class="markdown-alert-note"><p>Note blockquote</p></blockquote>

Full specs here.

I tried enabling it in markdown::markdown::markdown_to_html with just:

/// ...
  opts.insert(Options::ENABLE_GFM);

and it seems to work correctly.

I was wondering if it would be possible to add this feature to Zola, so I asked here before opening a PR.

2

See Enable blockquote tags · Issue #2719 · getzola/zola · GitHub

For this option in particular I don’t think it’s very compelling to add