Document process for adding WebIDL / managing web-sys crate

[ryankurte]

Hey there,

Looking at webusb support (#1694) and I've hit a dead end on how to add or manage webidl files, #1950 and the web-sys readme seem to suggest one can add webidl files and that the interface objects are generated from these, however, it's not clear from the wasm book or readme how to perform this generation step (and there don't seem to be any obvious build.rs or cargo / test scripts for this)?

It'd be neat to document this so it's easy for others to contribute idl files ^_^

Cheers,

ryan

[alexcrichton]

We have some rudimentary documentation for this here, but it's likely dated. Would be great to bring it up to speed!

[Pauan]

Here are the current directions. If you're adding stable APIs then it should go into web-sys/webidls/enabled, or if you're adding unstable APIs then it should go into web-sys/webidls/unstable.