Highlight specs that are still at an incubation level for features that are baseline

[captainbrosset]

For example, the requestVideoFrameCallback feature is about to become Baseline Low in a few weeks, as Firefox 132 goes to Stable.
This is great, but the spec is still at the incubation level.

Knowing what that happens seems useful information from a standardization perspective. Maybe not so much from a developer's perspective, but the explorer is mostly a playground at this point, so could very well be used to experiment with surfacing this information somehow.

The explorer already uses web-features and browser-specs, so it probably already has the data needed to achieve this.

@tidoust has already taken a crack at this actually, from the reverse angle. See https://github.com/tidoust/web-features-standardization, which starts from specs and reports the ones that ought to be more advanced from a standardization perspective given the status of implementations of some of the features they define.

I thought I'd capture this as a new issue anyway. Might become something we want to do at some point.