missing imports added

Author: michalkucharczyk

src/lib.rs

@@ -43,9 +43,9 @@ pub extern crate rand_core;
 #[cfg(feature = "serde")]
 pub extern crate serde;
 
+use alloc::{borrow::Cow, string::ToString, vec::Vec};
 use core::{fmt, str};
 
-use alloc::borrow::Cow;
 #[cfg(feature = "std")]
 use std::error;