This is the mirror image of #2170.

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- [x] Add new / update outdated documentation

package:
  name: beautifulsoup4
  version: 4.10.0
requirements:
  run:
    - soupsieve
source:
  sha256: 9a315ce70049920ea4572a4055bc4bd700c940521d36fc858205ad4fcde149bf
  url: https://files.pythonhosted.org/packages/69/bf/f0f194d3379d3f3347478bd267f754fc68c11cbf2fe302a6ab69447b1417/beautifulsoup4-4.10.0-py3-none-any.whl
test:
  imports:
    - bs4

package:
  name: beautifulsoup4
  version: 4.10.0
requirements:
  run:
    - soupsieve
source:
  sha256: 9a315ce70049920ea4572a4055bc4bd700c940521d36fc858205ad4fcde149bf
  url: https://files.pythonhosted.org/packages/69/bf/f0f194d3379d3f3347478bd267f754fc68c11cbf2fe302a6ab69447b1417/beautifulsoup4-4.10.0-py3-none-any.whl
test:
  imports:
    - bs4
