Request for spec documentation: all new index spaces and their contents listed in one place

[fitzgen]

One thing I keep stumbling over whenever I dig into the component model is what all the new index spaces are and what is in them, in one easy-to-scan place.

For example, I was trying to determine whether component types and defined types are in the same index space. That is really hard to determine right now when reading the explainer.

[lukewagner]

I suppose the main point of reference is the definition of sort in the explainer or the binary format. In particular: each sort gets an index space (indexed by, e.g., a sortidx). Thus, since both component types and defined types both have sort type, they'd go in the same index space. For new documentation, are you imagining some sort of "Index Spaces" section that lists and describes the index spaces, like this one in the core spec?

[fitzgen]

Yeah something like that. This has been the sort (ha) of question I want to answer for myself most often when reading the explainer and I don't feel like I come away sure of the answer.

[lukewagner]

Opened #264