HTML parser: Collapsible content

[NorthDecoder]

Although react-markdown package claims to do Github Flavored
Markdown (GFM), the demo appears to implement the
syntax differently than the marked.js demo.

The following works in marked.js demo (and on github flavored markdown):

## collapsible markdown?

<details><summary>CLICK ME</summary>
<p>

#### yes, even hidden code blocks!

```python
print("hello world!")
```

</p>
</details>

By removing spacing you can coax the react-markdown
demo to sort of work, but the collapsed content loses
the markdown translation:

## collapsible markdown?

<details><summary>CLICK ME</summary>
<p>
#### yes, even hidden code blocks!
```python
print("hello world!")
```

</p>
</details>

---

The collapsible markdown works in GFM

CLICK ME

yes, even hidden code blocks!

print("hello world!")

---

Reference PrISM isssue (84)[https://github.com/NorthwestGreenChemistry/PrISM/issues/84]

[ChristianMurphy]

This will be resolved by #428

implement the syntax differently than the marked.js

Right, because marked.js isn't commonmark or GFM compatible, see markedjs/marked#1202

[wooorm]

This should be solved by landing GH-563 today, which will soon be released in v6.0.0!

[murugaratham]

Does it work just by adding GFM? when i add GFM plug-in, it just render them as text

[wooorm]

<details> has nothing to do with GFM. It is an HTML feature. So see the HTML in markdown section in the readme.