Implement metatype proc-macro

crates/luaify/src/generate.rs

@@ -14,7 +14,7 @@ pub fn generate(expr: &Expr) -> Result<TokenStream> {
     Ok(f.done())
 }
 
-#[derive(Debug, Default)]
+#[derive(Default)]
 struct Formatter {
     buf: String,
     space: bool,