order derivable traits lists

Ignoring :
 - **generated**.rs
 - python/tidy/servo_tidy_tests/rust_tidy.rs

components/style/custom_properties.rs

@@ -39,7 +39,7 @@ pub fn parse_name(s: &str) -> Result<&str, ()> {
 ///
 /// We preserve the original CSS for serialization, and also the variable
 /// references to other custom property names.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub struct SpecifiedValue {
     css: String,