bug: Incorrectly handling `<!-- /// --->` tag

[silas]

Description

This is potentially/probably a bug in html5ever, but I figured I'd open it here first.

Something in the HTML to markdown pipeline is mishandling the <!-- /// ---> tag. Specifically anything after this tag is being dropped.

Steps to reproduce

1. Open demo page
2. Enter the following HTML

   <h1>One</h1>
   
   <!-- /// --->
   
   <p>Two</p>

3. Notice the output

   # One

[silas]

I did notice that if you open another broken tag, it will resume parsing the HTML.

<h1>One</h1>

<!-- /// --->

<p>Two</p>

<!-

<p>Three</p>

Results in the following:

# One

Three