Fix clippy complains

core/lib.rs

@@ -60,7 +60,7 @@ use std::{
     num::NonZero,
     ops::Deref,
     rc::Rc,
-    sync::{atomic::Ordering, Arc},
+    sync::Arc,
 };
 #[cfg(feature = "fs")]
 use storage::database::DatabaseFile;

core/storage/pager.rs

@@ -971,7 +971,7 @@ impl Pager {
     #[allow(clippy::readonly_write_lock)]
     pub fn allocate_page(&self) -> Result<PageRef> {
         let old_db_size = header_accessor::get_database_size(self)?;
-        #[allow(clippy::unused_mut)]
+        #[allow(unused_mut)]
         let mut new_db_size = old_db_size + 1;
         self.is_empty.store(false, Ordering::SeqCst);