Can't set endianess on C-like struct variant

[ckoehler]

See below. Is that intended?

#[derive(Nom)]
#[nom(LittleEndian)] // this works
#[nom(Selector = "u8")]
pub enum Foo {
    #[nom(Selector = "0")]
    #[nom(BigEndian)] // this does nothing
    First {
        #[nom(BigEndian)] // this works
        the_field: u16,
        
        // more fields
    },
    // ... 
}