Fix clippy lints

src/headers/header_name.rs

@@ -129,7 +129,7 @@ impl PartialEq<String> for HeaderName {
     }
 }
 
-impl<'a> PartialEq<&String> for HeaderName {
+impl PartialEq<&String> for HeaderName {
     fn eq(&self, other: &&String) -> bool {
         match HeaderName::from_str(other) {
             Err(_) => false,

src/headers/header_value.rs

@@ -125,7 +125,7 @@ impl PartialEq<String> for HeaderValue {
     }
 }
 
-impl<'a> PartialEq<&String> for HeaderValue {
+impl PartialEq<&String> for HeaderValue {
     fn eq(&self, other: &&String) -> bool {
         &&self.inner == other
     }

src/headers/header_values.rs

@@ -123,7 +123,7 @@ impl PartialEq<String> for HeaderValues {
     }
 }
 
-impl<'a> PartialEq<&String> for HeaderValues {
+impl PartialEq<&String> for HeaderValues {
     fn eq(&self, other: &&String) -> bool {
         self.inner.len() == 1 && self.inner[0] == **other
     }

src/status.rs

@@ -172,7 +172,7 @@ mod test {
 
     #[test]
     fn construct_shorthand_with_valid_status_code() {
-        let _res = Some(()).status(200).unwrap();
+        Some(()).status(200).unwrap();
     }
 
     #[test]
@@ -180,6 +180,6 @@ mod test {
     fn construct_shorthand_with_invalid_status_code() {
         let res: Result<(), std::io::Error> =
             Err(std::io::Error::new(std::io::ErrorKind::Other, "oh no!"));
-        let _res = res.status(600).unwrap();
+        res.status(600).unwrap();
     }
 }

src/status_code.rs

@@ -725,7 +725,7 @@ mod test {
         assert_eq!(StatusCode::Accepted, status_code);
         assert_eq!(
             Some(202),
-            serde_json::to_value(&StatusCode::Accepted)?.as_u64()
+            serde_json::to_value(StatusCode::Accepted)?.as_u64()
         );
         Ok(())
     }