reference: Factor out discussion of types from type declarations. Try (but probably fail) to explain variance in the page on types. I think the only way to understand variance is to try to explain it to someone else. Readers will still not really understand, but I cam away a bit more comfortable with the whole thing.
reference: More titivating of the doc on types and type declarations
reference: revise the reference on all the declarations, so the usage has a "general form" (not a grammar) each of whose elements are discussed in subsections of the discussion.