Wasmtime component bindgen: opt-in trappable error types (#5397)

* wip

* start trying to write a runtime test

* cut out all the more complex test cases until i get this one working

* add macro parsing for the trappable error type config

* runtime result tests works for an empty and a string error type

* debugging: macro is broken because interfaces dont have names???

* thats how you name interfaces

* record error and variant error work

* show a concrete trap type, remove debug

* delete clap annotations from wit-bindgen crate

these are not used - clap isnt even an optional dep here - but were a holdover from the old home

tests/all/component_model/bindgen.rs

@@ -5,6 +5,8 @@ use wasmtime::{
     Store,
 };
 
+mod results;
+
 mod no_imports {
     use super::*;