Accessibility in accordion panel

[brichet]

This PR fixes an accessibility issue about accordion panel:

• removes the role tab to the title, which is not in a tablist element.
• adds an ID to the widgets if necessary, to correctly link the aria-controls attribute of the corresponding title.

[fcollonval]

Thanks @brichet

I guess you use the Renderer to reuse the uuid. But could you please prefer not changing any public API and add the id if it does not exist in AccordionLayout.insertWidget - inherited from https://github.com/jupyterlab/lumino/blob/main/packages/widgets/src/panellayout.ts#L87

[brichet]

I guess you use the Renderer to reuse the uuid. But could you please prefer not changing any public API and add the id if it does not exist in AccordionLayout.insertWidget - inherited from https://github.com/jupyterlab/lumino/blob/main/packages/widgets/src/panellayout.ts#L87

Thanks for review @fcollonval

[fcollonval]

Thanks @brichet for the changes.

Could you add assertions to the tests and run yarn run api to update the API files (the associated CI job is failing).

[fcollonval]

I think you cannot just call expect, you need to add an assertion like

expect(w1.id).to.be.undefined;

For test equality, you should use expect(a).to.equal('value');

You can look at the chai library to see what is available.

Could you fix the test at line 123 that probably misguided you as it was missing an assertion.

[brichet]

I wanted to make sure the tests pass 😄
Thanks for noticing.

[fcollonval]

Thanks @brichet