clippy fixes (#2296)

actix-http/src/config.rs

@@ -104,6 +104,8 @@ impl ServiceConfig {
     }
 
     /// Returns the local address that this server is bound to.
+    ///
+    /// Returns `None` for connections via UDS (Unix Domain Socket).
     #[inline]
     pub fn local_addr(&self) -> Option<net::SocketAddr> {
         self.0.local_addr

actix-http/src/error.rs

@@ -55,6 +55,8 @@ impl Error {
         Self::new(Kind::Io)
     }
 
+    // used in encoder behind feature flag so ignore unused warning
+    #[allow(unused)]
     pub(crate) fn new_encoder() -> Self {
         Self::new(Kind::Encoder)
     }