Allow *any* unused code in doc tests

Author: dhardy

src/lib.rs

@@ -23,7 +23,7 @@
 #![deny(missing_docs)]
 #![deny(missing_debug_implementations)]
 #![deny(clippy::undocumented_unsafe_blocks)]
-#![doc(test(attr(allow(unused_variables), deny(warnings))))]
+#![doc(test(attr(allow(unused), deny(warnings))))]
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![no_std]