Merge pull request #3 from Sajjon/custom-type-rework

Allow 'External' errors from crate X to be used in crate Y

uniffi_bindgen/src/interface/mod.rs

@@ -1118,7 +1118,9 @@ fn throws_name(throws: &Option<Type>) -> Option<&str> {
  // Type has no `name()` method, just `canonical_name()` which isn't what we want.
  match throws {
  None => None,
- Some(Type::Enum { name, .. }) | Some(Type::Object { name, .. }) => Some(name),
+ Some(Type::Enum { name, .. })
+ | Some(Type::Object { name, .. })
+ | Some(Type::External { name, .. }) => Some(name),
  _ => panic!("unknown throw type: {throws:?}"),
  }
 }