Markdoc shiki code does not render inside an if tag

[taktran]

Astro Info

Astro                    v4.13.2
Node                     v18.20.3
System                   Linux (x64)
Package Manager          npm
Output                   static
Adapter                  none
Integrations             @astrojs/markdoc

If this issue only occurs in one browser, which browser is a problem?

No response

Describe the Bug

Using shiki code highlighting inside a markdoc if tag results in nothing being rendered (including other content inside the if tag).

What's the expected result?

In this .mdoc file:

{% if equals("true", "true") %}
Inside truthy

```js
const hello = "yes";
```

{% /if %}

I expect to see Inside truthy and the code block rendered using shiki highlighting, however all the contents inside the if are not shown at all: https://stackblitz.com/edit/github-jw5bfh?file=src%2Fcontent%2Fdocs%2Fintro.mdoc

I've replicated this with shiki commented out: https://stackblitz.com/edit/github-jw5bfh-xsgvdw?file=src%2Fcontent%2Fdocs%2Fintro.mdoc,markdoc.config.mjs - here the text and code are shown.

Link to Minimal Reproducible Example

https://stackblitz.com/edit/github-jw5bfh?file=src%2Fcontent%2Fdocs%2Fintro.mdoc

Participation

• I am willing to submit a pull request for this issue.

[taktran]

I copied over the Astro Shiki extension and console logged the results when parsing a .mdoc file, and it seems like the extension is returning the correct output, so I'm thinking it's the Astro/Markdoc wrapping around it.

.mdoc

{% if isFramework("react") %}
react code
```js
const js = "hello";
```
{% /if %}

Inside the shiki extension

console.log({
    lang,
    content: attributes.content,
    html,
    unescaped: unescapeHTML(html),
});

Console

{
  lang: 'js',
  content: 'const js = "hello";\n',
  html: '<pre class="astro-code astro-code-themes github-light github-dark" style="background-color:#fff;--shiki-dark-bg:#24292e;color:#24292e;--shiki-dark:#e1e4e8; overflow-x: auto; white-space: pre-wrap; word-wrap: break-word;" tabindex="0" data-language="js"><code><span class="line"><span style="color:#D73A49;--shiki-dark:#F97583">const</span><span style="color:#005CC5;--shiki-dark:#79B8FF"> js</span><span style="color:#D73A49;--shiki-dark:#F97583"> =</span><span style="color:#032F62;--shiki-dark:#9ECBFF"> "hello"</span><span style="color:#24292E;--shiki-dark:#E1E4E8">;</span></span>\n' +
    '<span class="line"></span></code></pre>',
  unescaped: [String (HTMLString): '<pre class="astro-code astro-code-themes github-light github-dark" style="background-color:#fff;--shiki-dark-bg:#24292e;color:#24292e;--shiki-dark:#e1e4e8; overflow-x: auto; white-space: pre-wrap; word-wrap: break-word;" tabindex="0" data-language="js"><code><span class="line"><span style="color:#D73A49;--shiki-dark:#F97583">const</span><span style="color:#005CC5;--shiki-dark:#79B8FF"> js</span><span style="color:#D73A49;--shiki-dark:#F97583"> =</span><span style="color:#032F62;--shiki-dark:#9ECBFF"> "hello"</span><span style="color:#24292E;--shiki-dark:#E1E4E8">;</span></span>\n' +
    '<span class="line"></span></code></pre>']
}