### Bug description

From #3847, it seems like it should be possible to use fenced divs to indicate that a section of Markdown in .qmd should be converted into two separate Markdown cells in Jupyter, but this does not seem to be the case.

Tested on Quarto v1.2.335, on both Arch Linux and Ubuntu 22.04.

Here is a sample file `simple.qmd`:

```markdown
---
title: Simple version
---

# Lorem ipsum

**Lorem ipsum** dolor sit amet, consectetur adipiscing elit. Nunc luctus
bibendum felis dictum sodales.

:::::: {.cell .markdown}
# Lorem ipsum

**Lorem ipsum** dolor sit amet, consectetur adipiscing elit. Nunc luctus
bibendum felis dictum sodales.
::::::
```

Expected Jupyter notebook after running `quarto convert simple.qmd`:

```json
{
  "cells": [
    {
      "cell_type": "raw",
      "metadata": {},
      "source": [
        "---\n",
        "title: Simple version\n",
        "---"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "# Lorem ipsum\n",
        "\n",
        "**Lorem ipsum** dolor sit amet, consectetur adipiscing elit. Nunc luctus\n",
        "bibendum felis dictum sodales.\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\n",
        "# Lorem ipsum\n",
        "\n",
        "**Lorem ipsum** dolor sit amet, consectetur adipiscing elit. Nunc luctus\n",
        "bibendum felis dictum sodales."
      ]
    }
  ],
  "metadata": {
    "kernelspec": {
      "display_name": "Python 3 (ipykernel)",
      "language": "python",
      "name": "python3"
    }
  },
  "nbformat": 4,
  "nbformat_minor": 4
}
```

Actual Jupyter notebook output (`simple.ipynb`):

```json
{
  "cells": [
    {
      "cell_type": "raw",
      "metadata": {},
      "source": [
        "---\n",
        "title: Simple version\n",
        "---"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "# Lorem ipsum\n",
        "\n",
        "**Lorem ipsum** dolor sit amet, consectetur adipiscing elit. Nunc luctus\n",
        "bibendum felis dictum sodales.\n",
        "\n",
        ":::::: {.cell .markdown}\n",
        "# Lorem ipsum\n",
        "\n",
        "**Lorem ipsum** dolor sit amet, consectetur adipiscing elit. Nunc luctus\n",
        "bibendum felis dictum sodales.\n",
        "::::::"
      ]
    }
  ],
  "metadata": {
    "kernelspec": {
      "name": "python3",
      "language": "python",
      "display_name": "Python 3 (ipykernel)"
    }
  },
  "nbformat": 4,
  "nbformat_minor": 4
}
```

As a side note, the command mentioned in #3847 (`quarto convert simple.qmd --to ipynb`) does not work, and the `--to` option does not appear in the output of `quarto help convert`. It may be that there's another setup step or command flag that I've missed, but I couldn't seem to find a fix.

### Checklist

- [X] Please include a minimal, fully reproducible example in a single .qmd file? Please provide the whole file rather than the snippet you believe is causing the issue.
- [X] Please [format your issue](https://quarto.org/bug-reports.html#formatting-make-githubs-markdown-work-for-us) so it is easier for us to read the bug report.
- [X] Please document the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] Please document the operating system you're running. If on Linux, please provide the specific distribution.
2023-02-02T19:21:33Z
syclops
bug
closed
Cannot generate separate Markdown cells in Jupyter
https://github.com/quarto-dev/quarto-cli/issues/4195