chore(lib): remove importing prelude AsRef trait

Author: tottoto

src/method.rs

@@ -18,7 +18,6 @@
 use self::extension::{AllocatedExtension, InlineExtension};
 use self::Inner::*;
 
-use std::convert::AsRef;
 use std::convert::TryFrom;
 use std::error::Error;
 use std::str::FromStr;