WIT - inline definitions

Not pressing by any means, more nice-to-have, but thought I'd post while I'm thinking about it.

Just like one can define an inline tuple or result, it could be useful to define inline definitions.

That is, instead of:

enum error {
  error-a,
  error-b
}
record param-type {
  name: string,
  value: option<string>
}
func p: (param: param-type) -> result<_, error>

Writing:

func p: (param: record {
  name: string,
  value: option<string>
}) -> result<_, enum {
  error-a,
  error-b
}>

Where the above could be internalized as sugar for some anonymous type naming scheme (ideally derived from the function and param name itself, as opposed to its structure).

The issue proposes inline WIT record and enum definitions as syntax sugar for anonymous types, but names no files, tests, or implementation entry points. Start by reviewing the existing WIT type-definition and function-signature specification; done requires an agreed design for naming, scoping, and semantics before implementation can begin.