Don't render table of contents if there are no list items

[ZachSaucier]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)

Problem

The way that this currently works, it renders this:

<nav class="toc"><ol class="toc-level toc-level-1"></ol></nav>

This is extra, unnecessary markup. Additionally, if one uses CSS to add something (I use it to add "Table of contents" before the <ol>), it shows up even there's no table of contents to see.

Solution

The whole table of contents should not be rendered if there are no <li> items.

Alternatives

I don't think there are alternatives?

[ZachSaucier]

Dang it, wrong repo. Sorry about that.