DeJson macro fails for tuple-like and struct-like enum variants with trailing commas

[tadeohepperle]

For example this does not compile:

#[derive()
#[derive(Debug, Clone, SerJson, DeJson)]
enum MyEnum {
    A,
    B,
    EnumVariantWithVeryLongNameSoRustFmtPutsATrailingCommaBehindLastVariant(
       String, 
       String, 
    )
}

because the parser in the proc macro crate thinks there is another field after the trailing comma.