Document per-item versions using @since gates

[yoshuawuyts]

Depends on WebAssembly/component-model#332 to be merged first. This documents the stability of all items using the @since gate notation, enabling WIT documents to be updated over time without major compatibility hazards.

While filing this patch I also saw there is a 0.3.0-draft document checked in. I wasn't sure what to do with that so I've omitted it from this PR for now. We should follow up on that later.

For an overview of how this would apply to all existing WASI APIs, including the unstable timezone API, see WebAssembly/WASI#604. Thanks!

[yoshuawuyts]

If I try running wit-bindgen markdown wit --features= --html-in-md to resolve the CI failure, I get the following error:

thread 'main' panicked at /Users/yosh/.cargo/registry/src/index.crates.io-6f17d22bba15001f/wit-parser-0.209.1/src/resolve.rs:2105:21:
assertion `left == right` failed
  left: Interface { id: Id { idx: 1 }, stability: Stable { since: Version { major: 0, minor: 2, patch: 0 }, feature: None } }
 right: Interface { id: Id { idx: 1 }, stability: Unknown }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Not sure what's going on yet, but will have to dig in further.

[yoshuawuyts]

bytecodealliance/wasm-tools#1669 seems to resolve the CI issue. That means in order to resolve this, we need to take the following steps:

• merge Better handle stability attributes when merging WIT packages bytecodealliance/wasm-tools#1669
• publish a new version of wasm-tools
• publish a new version of wit-bindgen-cli
• publish a new version of wit-bindgen-up-to-date
• update this PR to use the new version of wit-bindgen-up-to-date

[yoshuawuyts]

Or actually, what perhaps just needs to happen is for us to merge the PR on wasi:cli, and then run wit-deps update again on this.