Merge 'Remove duplicated attribute in ' from bit-aloo

Removed the redundant `#![allow(clippy::arc_with_non_send_sync)]` from
wal.rs, since it’s already defined in `mod.rs`.

Closes #2764

core/storage/wal.rs

@@ -1,4 +1,3 @@
-#![allow(clippy::arc_with_non_send_sync)]
 #![allow(clippy::not_unsafe_ptr_arg_deref)]
 
 use std::array;