Markdown-GFM: not escaping HTML in text

[fredck]

📝 Provide detailed reproduction steps (if any)

1. Go to the markdown demo.
2. Type some text which contains HTML in it, like "<h1>Test</h1>".

✔️ Expected result

The output should be \<h1>Test\</h1>, according to the GFM specs.

❌ Actual result

Current output: <h1>Test</h1>.

[jodator]

It looks like fixed by the #7307 .