feat(de): Rename de::Error trait methods

serde_tests/tests/test_bytes.rs

@@ -10,19 +10,13 @@ use serde::bytes::{ByteBuf, Bytes};
 struct Error;
 
 impl serde::ser::Error for Error {
-    fn syntax(_: &str) -> Error { Error }
-
-    fn invalid_value(_field: &str) -> Error { Error }
+    fn custom(_: String) -> Error { Error }
 }
 
 impl serde::de::Error for Error {
-    fn syntax(_: &str) -> Error { Error }
+    fn custom(_: String) -> Error { Error }
 
     fn end_of_stream() -> Error { Error }
-
-    fn unknown_field(_field: &str) -> Error { Error }
-
-    fn missing_field(_field: &'static str) -> Error { Error }
 }
 
 impl fmt::Display for Error {

serde_tests/tests/token.rs

@@ -416,7 +416,7 @@ pub enum Error {
 }
 
 impl ser::Error for Error {
-    fn syntax(_: &str) -> Error { Error::SyntaxError }
+    fn custom(_: String) -> Error { Error::SyntaxError }
 
     fn invalid_value(msg: &str) -> Error {
         Error::InvalidValue(msg.to_owned())
@@ -424,7 +424,7 @@ impl ser::Error for Error {
 }
 
 impl de::Error for Error {
-    fn syntax(_: &str) -> Error { Error::SyntaxError }
+    fn custom(_: String) -> Error { Error::SyntaxError }
 
     fn end_of_stream() -> Error { Error::EndOfStreamError }