Update src/lib.rs

Co-authored-by: Jack Wrenn <[email protected]>

Author: mmirate

src/lib.rs

@@ -59,8 +59,7 @@ use alloc::{
 
 pub use either::Either;
 
-#[cfg(feature = "use_std")]
-use std::borrow::Borrow;
+use core::borrow:Borrow;
 #[cfg(feature = "use_std")]
 use std::collections::HashMap;
 use std::iter::{IntoIterator, once};