Include WebAssembly as having *undefined* type

[guybedford]

The specification currently notes that the HTML integration would treat JavaScript as assertion "type" *undefined*. This updates that note to treat Web Assembly similarly as assertion "type" being *undefined*.

Effectively this specification note already implies today that assert { type: 'javascript' } should not be implemented, and then extends that to assert { type: 'webassembly' }.

Alternatives to this PR include the "any" proposal, "executable" proposal, or "javascript" and "webassembly" direct types.

[GeoffreyBooth]

The readme should be updated as well, including the WebAssembly examples there.

[GeoffreyBooth]

Also, this is part of a section called “A Sample host integration: The Web embedding”—it’s an example of how a host could implement the spec, not the spec itself. As in, a host could decide to treat JavaScript as undefined, as in this example, but it doesn’t need to because this is just an example implementation. If you want to define the lack of a declared assertion type as meaning type: undefined then it should be clearly explained as such within the spec itself, as well as in the proposal readme and examples. Such a change would force an update in the HTML spec, because their treatment of “lack of type = 'javascript'“ would then be in violation.

[ljharb]

Is this still relevant? If so, can it be rebased?

[nicolo-ribaudo]

Given that:

• this change is not normative, but only descriptive of a possible web integration
• WASM-ESM integration is not currently being developed
• HTML ended up not using an undefined type of JS internally I'm closing this PR. @guybedford If you'd prefer to re-open and land this let me know!