Fix some clippy lints.

Author: sunfishcode

src/http/fields.rs

@@ -20,7 +20,7 @@ pub(crate) fn header_map_to_wasi(header_map: &HeaderMap) -> Result<Fields, ToWas
     for (key, value) in header_map {
         // Unwrap because `HeaderMap` has already validated the headers.
         wasi_fields
-            .append(&key.as_str(), &value.as_bytes())
+            .append(key.as_str(), value.as_bytes())
             .map_err(|error| ToWasiHeaderError {
                 error,
                 context: format!("header {key}: {value:?}"),

src/http/request.rs

@@ -42,7 +42,7 @@ pub(crate) fn try_into_outgoing<T>(request: Request<T>) -> Result<(OutgoingReque
     // Set the url path + query string
     if let Some(p_and_q) = parts.uri.path_and_query() {
         wasi_req
-            .set_path_with_query(Some(&p_and_q.as_str()))
+            .set_path_with_query(Some(p_and_q.as_str()))
             .map_err(|()| {
                 Error::other(format!("path and query rejected by wasi-http {p_and_q:?}"))
             })?;

src/http/server.rs

@@ -109,7 +109,7 @@ impl Responder {
         if let Some(len) = body.len() {
             let mut buffer = itoa::Buffer::new();
             wasi_headers
-                .append(&CONTENT_LENGTH.as_str(), &buffer.format(len).as_bytes())
+                .append(CONTENT_LENGTH.as_str(), buffer.format(len).as_bytes())
                 .unwrap();
         }
 
@@ -171,7 +171,7 @@ impl Finished {
         drop(stream);
 
         // If there was an I/O error, panic and don't call `OutgoingBody::finish`.
-        let _ = result.expect("I/O error while writing the body");
+        result.expect("I/O error while writing the body");
 
         let wasi_trailers =
             trailers.map(|trailers| header_map_to_wasi(&trailers).expect("header error"));