Update lib.rs

Author: huacnlee

crates/macro/src/lib.rs

@@ -329,8 +329,6 @@ fn generate_code(
     quote! {
         use rust_i18n::{BackendExt, CowStr, MinifyKey};
         use std::borrow::Cow;
-        use std::sync::Mutex;
-        use rust_i18n::once_cell::sync::Lazy;
 
         /// I18n backend instance
         ///