This is the mirror image of #2170.

### Checklists

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- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests
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Add `default_converter` argument to `to_js` and `toJs`. This is the mirror image of #2170.

### Checklists

<!-- Note on checklists:
     If you think some of these steps are not necessary for your PR,
     just remove those checkboxes, or mark them as checked. Otherwise,
     if some checkboxes are left unmarked, we might assume that your PR
     is not ready to be merged and we might keep you waiting -->

- [x] Add a [CHANGELOG](https://github.com/pyodide/pyodide/blob/main/docs/project/changelog.md) entry
- [x] Add / update tests
- [x] Add new / update outdated documentation

import subprocess
from pathlib import Path

BASE_DIR = Path(__file__).parents[3]


def test_run_docker_script():
    res = subprocess.run(
        ["bash", str(BASE_DIR / "run_docker"), "--help"],
        check=False,
        capture_output=True,
    )

    assert "Usage: run_docker" in res.stdout.decode("utf-8")

    res = subprocess.run(
        ["bash", str(BASE_DIR / "run_docker"), "--invalid-param"],
        check=False,
        capture_output=True,
    )
    assert res.returncode > 0
    assert "Unknown option --invalid-param" in res.stderr.decode("utf-8")

import subprocess
from pathlib import Path

BASE_DIR = Path(__file__).parents[3]


def test_run_docker_script():
    res = subprocess.run(
        ["bash", str(BASE_DIR / "run_docker"), "--help"],
        check=False,
        capture_output=True,
    )

    assert "Usage: run_docker" in res.stdout.decode("utf-8")

    res = subprocess.run(
        ["bash", str(BASE_DIR / "run_docker"), "--invalid-param"],
        check=False,
        capture_output=True,
    )
    assert res.returncode > 0
    assert "Unknown option --invalid-param" in res.stderr.decode("utf-8")
