Convert many object types structs to use C99 tagged initializer syntax.
diff --git a/py/objexcept.c b/py/objexcept.c
index ec03b9b..22b8c58 100644
--- a/py/objexcept.c
+++ b/py/objexcept.c
@@ -45,7 +45,7 @@
     NULL, // binary_op
     NULL, // getiter
     NULL, // iternext
-    {{NULL, NULL},}, // method list
+    .methods = {{NULL, NULL},},
 };
 
 mp_obj_t mp_obj_new_exception(qstr id) {