Use formal wit syntax within doc?

I noticed that for explaning event in explainer, it is written as:

variant event {
    none,
    subtask(subtask-index, subtask-state),
    stream-read(stream-index, stream-result),
    stream-write(stream-index, stream-result),
    future-read(future-index, future-read-result),
    future-write(future-index, future-write-result),
    task-cancelled,
}

However, per cm ast, it says:

defvaltype    ::= bool
                | s8 | u8 | s16 | u16 | s32 | u32 | s64 | u64
                | f32 | f64
                | char | string
                | error-context 📝
                | (record (field "<label>" <valtype>)+)
                | (variant (case "<label>" <valtype>?)+)

Although I assume the event is never lowered / lifted in the same way as variants (the code is returned directly and the data are picked up from the memory, or passed as arguments in callback style), is it possible that we use some consistent way to describe it, or relax the restriction on variant?

Start by comparing the event example in the explainer with the defvaltype grammar attributed to the component-model AST. Determine whether the documentation should use formal syntax or explain an exception for events; done means the syntax and its rationale are consistent and the relevant documentation is updated.