### Bug description

It seems that the crossref is not being converted to python notebook format when using `quarto convert`. A MRE is as follows,

````md
---
title: Ref in converted `ipynb`
---

```{python} 
# a code chunk
print("See below")
```

$$
E = mc^2
$$ {#eq-example}

See an example, @eq-example.

````

This `mre.qmd` file was then converted to a notebook using `quarto convert mre.qmd`.

When the converted `ipynb` file is opened, the crossref is not working as expected.

![Screenshot from 2022-06-14 09-22-44](https://user-images.githubusercontent.com/60116296/173628756-0fcc3637-f936-4d45-8e64-4a8200d527a1.png)

```bash
❯ quarto check

[✓] Checking Quarto installation......OK
      Version: 99.9.9
      Path: /home/julian/quarto-cli/package/dist/bin

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.10.4
      Path: /usr/bin/python3
      Jupyter: 4.10.0
      Kernels: python3

[✓] Checking Jupyter engine render....OK

[✓] Checking R installation...........OK
      Version: 4.1.2
      Path: /usr/lib/R
      LibPaths:
        - /home/julian/R/x86_64-pc-linux-gnu-library/4.1
        - /usr/local/lib/R/site-library
        - /usr/lib/R/site-library
        - /usr/lib/R/library
      rmarkdown: 2.14

[✓] Checking Knitr engine render......OK

```
I am running popos (Linux Uhuntu 22.04)

### Checklist

- [X] [formatted your issue](https://yihui.org/issue/#please-format-your-issue-correctly) so it is easier for us to read?
- [X] included a minimal, self-contained, and reproducible example?
- [X] documented the quarto version you're running, by providing the output produced by `quarto check` in a terminal in your issue?
- [ ] documented the RStudio IDE version you're running (if applicable), by providing the value displayed in the "About RStudio" main menu dialog?
- [X] documented which operating system you're running? If on Linux, please provide the specific distribution as well.
- [X] upgraded to the latest version, including your versions of R, the RStudio IDE, and relevant R packages?
2022-06-14T16:33:03Z
juliantao
bug
closed
`quarto convert`: crossref not converted to ipynb format
https://github.com/quarto-dev/quarto-cli/issues/1151