explore/confirm the "common knowledge" foundation at the intersection of our spec readers

[michaelficarra]

In ECMA-262, we define all of the concepts we use that are not considered "common knowledge" to all of our readers. The editor group mostly determines what is "common knowledge" based on vibes. We may be over- or under-approximating what needs definition. It'd be nice to have some data that we can refer to to better inform our decisions here. What are we defining that we really don't need to? What are we using that's in need of further elaboration?