Add WebAssembly features, take 2

[Elchi3]

Taking over #1634

Specification URLs are tricky here. Not every feature has a proper spec or is integrated in the main wasm spec. Often there is just a markdown file to point to (BCD does this and we then have to add lots of URLs as exceptions for spec urls).

[autonome]

Another pass on descriptions, but haven't done a looksee into Caniuse. Are there any discrepancies there?

[autonome]

A couple more non-blocking description suggestions.

[ddbeck]

Partial review here. Main points so far:

• The "An extension to…" structure of these descriptions is a major departure from the rest of our descriptions. Other descriptions are complete sentences. I've made some suggestions to restructure these, but the unhappy side effect of having to write a complete sentence is that you have to know what you're saying and when it comes to wasm, I do not.

• For the IDs, I'm fine with wasm- prefixes, but for the names, I'd prefer to preserve the scanability of a list by either dropping the WebAssembly prefix (if it makes sense to do so) or moving it to a disambiguating suffix (e.g., Tail call optimzation (WebAssembly).

• I had no idea about the webassembly.api namespace in BCD. That is… unusual and surprising.

[Elchi3]

Thanks Daniel! Without the specs/explainers, it is really hard to tell what these things are. I pushed fe5acf7 to update the descriptions and to add spec urls.

I think I still need/want to:

• tell the linter to not complain about these urls
• (optional) group all these features in a "webassembly" group

[ddbeck]

@Elchi3 Great, thank you!

You can add exceptions here:

web-features/scripts/specs.ts

Lines 23 to 27 in e31b3b0

	const defaultAllowlist: allowlistItem[] = [
	// [
	// "https://example.com/spec/",
	// "Allowed because…. Remove this exception when https://example.com/org/repo/pull/1234 merges."
	// ]

Though if BCD is already doing this, I suppose we could "inherit" BCD's overrides on some automatic basis.

(Now that I'm saying this, checking the validity of a spec URL and fragment might make a nice little standalone package that we could share between BCD and web-features.)

[Elchi3]

Thanks for the quick response! I added to the exception list and also grouped the features.

(I'm improving spec URL validation even further in BCD [to also guarantee fragment validity with webref] but maybe web-specs itself could offer some such validations for all consumers [or, as you say, at some point we move this into a standalone package])

[ddbeck]

OK, I've suggested some more modifications to the descriptions. I think we're close. Take what you like and ignore the rest. Like the WebGL extensions, as long as we're giving folks a clue that this is not relevant to most web developers, then we'll probably be OK.

There is one thing that I feel moderately strong about: I'd like to preserve the existing wasm-simd ID, unless you think it's really worthy of a breaking release (or have other breaking changes you want to make soon).

[ddbeck]

Let's go!