Improve error message for invalid response lengths.

Author: arik-so

lightning-block-sync/src/http.rs

@@ -288,7 +288,7 @@ impl HttpClient {
 			HttpMessageLength::Empty => { Vec::new() },
 			HttpMessageLength::ContentLength(length) => {
 				if length == 0 || length > MAX_HTTP_MESSAGE_BODY_SIZE {
-					return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, "out of range"))
+					return Err(std::io::Error::new(std::io::ErrorKind::InvalidData, format!("invalid response length: {}", length)));
 				} else {
 					let mut content = vec![0; length];
 					#[cfg(feature = "tokio")]