clippy: allow new without default

src/arena.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::new_without_default)] // annotating structs annotated with #[bitfield] doesn't work
+
 #[cfg(feature = "http")]
 use crate::http::{HttpListener, HttpResponse};
 use crate::machine::loader::LiveLoadState;