Support for new style document icon for macOS Bug Sur

[GetToSet]

macOS Big Sur has been using a new way to define document icons with center image, background fill and text.

Adopting this kind of document icon can help making icons more consistent with those defined in system as well as other apps adopting this style.

[vscodenpa]

We closed this issue because we don't plan to address it in the foreseeable future. If you disagree and feel that this issue is crucial: we are happy to listen and to reconsider.

If you wonder what we are up to, please see our roadmap and issue reporting guidelines.

Thanks for your understanding, and happy coding!