Add conversion for affiliated keywords to wasm additional properties.

src/wasm/macros.rs

@@ -2,6 +2,19 @@
 ///
 /// This exists to make changing the type signature easier.
 macro_rules! to_wasm {
+    ($ostruct:ty, $istruct:ty, $original:ident, $wasm_context:ident, $fnbody:tt) => {
+        impl<'s, 'p> ToWasm<'p> for $istruct {
+            type Output = $ostruct;
+
+            fn to_wasm(
+                &'p self,
+                $wasm_context: crate::wasm::to_wasm::ToWasmContext<'_>,
+            ) -> Result<Self::Output, crate::error::CustomError> {
+                let $original = self;
+                $fnbody
+            }
+        }
+    };
     ($ostruct:ty, $istruct:ty, $original:ident, $wasm_context:ident, $standard_properties:ident, $fnbody:tt) => {
         impl<'s, 'p> ToWasm<'p> for $istruct {
             type Output = $ostruct;