commonmark specification for numered lists starting with arbitrary number seems violated

[epogrebnyak]

Describe the bug

I would like a new list to be numbered starting with 5 if 5 is specified:

5. Подготовка стенда:
   • [x] стенд включает все архитектурные элементы системы;

Here is sandbox for commonmark where rendering is correct.

In a more simple example:

5. Prep

is expected to render as

<ol start="5">
<li>Prep</li>
</ol>

Jupyter-book currently starts this numbering with 1, not 5.

Reproduce the bug

Render source code in markdown:

5. Prep

List your environment

λ jb --version
Jupyter Book      : 0.13.0
External ToC      : 0.2.4
MyST-Parser       : 0.15.2
MyST-NB           : 0.13.2
Sphinx Book Theme : 0.3.3
Jupyter-Cache     : 0.4.3
NbClient          : 0.5.3