`generate.js` doc tool produces incomplete json

[gromnitsky]

The output from

$ node generate.js ../../doc/api/debugger.markdown

doesn't correspond to its markdown source. For example, ### Info section is missing, both ### Execution control & ### Various sections lack expected desc property.

[Fishrock123]

cc @robertkowalski?

[Fishrock123]

Honestly, I don't think anyone has really maintained the docs tool in years. long-term plan is to replace it with some other community maintained documentation generator.

There is also a separate repo for it, though again, no-one maintains it. https://github.com/iojs/doc-tool

[Trott]

If we just want to patch in a fix here, this might be a good first contribution for someone. Tagging it as such. Feel free to remove the label if we don't really want this to get fixed here but would rather it get fixed in the separate repo.

If someone does fix it, they might also want to update the marked module that the tool depends on.

[firedfox]

This problem is caused by a bug processing unordered list which is directly following a heading.
Most of such lists are Commands reference, AFAICS.
In HTML result, an unordered list following a heading would be wrapped by a <div class="signature">, for instance:

### Various

* `scripts` - List all loaded scripts
* `version` - Display V8's version

would be converted to:

<h3>Various</h3>
<div class="signature">
  <ul>
    <li><code>scripts</code> - List all loaded scripts</li>
    <li><code>version</code> - Display V8&#39;s version</li>
  </ul>
</div>

Shall we also wrap the list in the JSON result? Such as:

{
  "textRaw": "Various",
  "name": "various",
  "desc": "<div class="signature"><ul><li><code>scripts</code> - List all loaded scripts</li>
<li><code>version</code> - Display V8&#39;s version</li></ul></div>",
  "type": "module",
  "displayName": "Various"
}

Or shall we just leave it alone without any wrapping?
Maybe I can make my first contribution once figure it out.

[Trott]

/cc @nodejs/documentation

[firedfox]

Above PR added a default case to processList function. All missing lists are put into desc as uls without any extra wrapping. The json is complete now.
This is the diff result generated from all.markdown before and after the patch: http://106.187.89.52/tmp/diff-json.html