Web version : download and infinite loop with editor when saved
Hi,

On https://kitao.github.io/pyxel/wasm/examples/image_editor.html, if I click on "save", it doesn't save the editor in the `Pyodide` filesystem but it downloads it indefinitely.
Same, with :
```
pyodide.runPython(`import pyxel.editor; pyxel.save("/pyxel_working_directory/res.pyxres")`);
```
Before, `res.pyxres` was saved in the Pyodide filesystem. Now, `res.pyxres` is downloaded.

I use Chrome and Windows.