hugo: Code block inside list not rendered as

 if containing lines starting with +, - or *

In Hugo 0.14/0.15 I noticed that code blocks are not rendered correctly if they contain lines starting with +, - or * and are nested inside a list.

Example:

1. Some list item

    ```plain
    + this doesn't work
    ```

The generated HTML is:

<ol>
    <li><p>Some list item</p>
    <p>```plain</p>
    <ul>
        <li>this doesn&rsquo;t work
        ```</li>
    </ul></li>
</ol>

Removing or replacing the offending character, prepending 4 spaces, or taking the block out of the list solves it.