adapt to recent wasm-tools changes

Author: cpetig

crates/wac-graph/src/encoding.rs

@@ -613,7 +613,7 @@ impl<'a> TypeEncoder<'a> {
         let cases = variant
             .cases
             .iter()
-            .map(|(n, ty)| (n.as_str(), ty.map(|ty| self.value_type(state, ty)), None))
+            .map(|(n, ty)| (n.as_str(), ty.map(|ty| self.value_type(state, ty))))
             .collect::<Vec<_>>();
 
         let index = state.current.encodable.type_count();