chore(lib): fix nightly unused warning about AsciiExt

src/header/common/link.rs

@@ -1,6 +1,7 @@
 use std::fmt;
 use std::borrow::Cow;
 use std::str::FromStr;
+#[allow(unused)]
 use std::ascii::AsciiExt;
 
 use mime::Mime;

src/header/common/mod.rs

@@ -142,6 +142,7 @@ macro_rules! test_header {
     ($id:ident, $raw:expr) => {
         #[test]
         fn $id() {
+            #[allow(unused)]
             use std::ascii::AsciiExt;
             let raw = $raw;
             let a: Vec<Vec<u8>> = raw.iter().map(|x| x.to_vec()).collect();

src/header/common/pragma.rs

@@ -1,4 +1,5 @@
 use std::fmt;
+#[allow(unused)]
 use std::ascii::AsciiExt;
 
 use header::{Header, Raw, parsing};

src/header/common/referrer_policy.rs

@@ -1,4 +1,5 @@
 use std::fmt;
+#[allow(unused)]
 use std::ascii::AsciiExt;
 
 use header::{Header, Raw, parsing};

src/header/shared/charset.rs

@@ -1,5 +1,6 @@
 use std::fmt::{self, Display};
 use std::str::FromStr;
+#[allow(unused)]
 use std::ascii::AsciiExt;
 
 use self::Charset::*;

src/header/shared/quality_item.rs

@@ -1,3 +1,4 @@
+#[allow(unused)]
 use std::ascii::AsciiExt;
 use std::cmp;
 use std::default::Default;