Function simple_enum_default_methods

fn simple_enum_default_methods<'a>(
    cls: &'a Ident,
    unit_variant_names: impl IntoIterator<Item = (&'a Ident, Cow<'a, Ident>, &'a Vec<&'a Attribute>)>,
    ctx: &Ctx,
) -> Vec<MethodAndMethodDef>