(Auto)EmbedLiveSample is not working correctly

See also https://github.com/mdn/content/pull/10758.

It seems that if a page has a structure like this:

## A heading

{{EmbedLiveSample}}

### HTML

(the HTML code block)

### JavaScript

(the JS code block)

…then the code blocks aren’t found. But they should be, according to the spec (https://github.com/mdn/content/discussions/5803#discussioncomment-842706), because they are in the same section as the {{EmbedLiveSample}} call. Perhaps the implementation isn’t looking in subsections of the current section?

[wbamberg]

no page at the moment starts with a live sample in level two ## intro section.

Except for the two that are referenced in https://github.com/mdn/content/pull/10758#issue-1062998747 ?

https://developer.mozilla.org/en-US/docs/web/html/element/input/date#examples https://developer.mozilla.org/en-US/docs/web/html/element/input/month#examples

Still as I said above:

If we do still want to start using it widely, I guess in practice it would be OK to disallow the particular usage that gives rise to this bug (it’s certainly niche) as fixing it looks hard.

[OnkarRuikar]

The issue exists. Following code

---
title: Authoring MathML
slug: Web/MathML/Authoring
tags:
  - Beginner
  - MathML
  - MathML Project
---

## A heading

{{EmbedLiveSample}}

### HTML

```html
<h1>hi!</h1>
```

### CSS

```css
h1 {
  color:red;
}
```

throws error:

Error: MacroLiveSampleError within .../index.md, line 11 column 19 (unable to find any live code samples for "19" within /en-US/docs/Web/MathML/Authoring)

This is a very low severity issue as no page at the moment starts with a live sample in level two ## intro section.