[accessibility] Interactive markers should have a default accessible name

[Malvoz]

Interactive markers (e.g. markers that bind to popups) should have a default accessible name, e.g. aria-label="Marker" if not specified.

Related WCAG 2.1 Success Criterion: 4.1.2 Name, Role, Value (this issue is to address the Name part of the Success Criterion for interactive markers).

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Furthermore, ideally developers should ensure that each marker has a unique and descriptive name, such that the user can know what the marker is visually highlighting (in the case of markers binding to popups it'd also allow AT users to know what it's for before opening the popup). For example, the marker in https://docs.mapbox.com/mapbox-gl-js/example/set-popup/ would ideally be named "Washington Monument" or similar. Perhaps developers can be warned if markers are not uniquely named?

[mourner]

Thanks so much for the thorough evaluations and hints @Malvoz! I've put all these issues in the accessibility milestone — seems like a lot of low-hanging fruits we could address quickly https://github.com/mapbox/mapbox-gl-js/milestone/48

[fergcody06]

We recently updated our Mapbox version to v2.6.0 to resolve a WCAG issue we were seeing where role="button" needed to be added to the markers. That issue is now resolved but it introduced a new WCAG issue where Aria buttons must be accompanied by an accessible name. This issue will solve that. Does anyone know when this is going out? I see it was added to the same PR that had the role="button" fix but was then removed before the merge to main branch.