fix silly mistake with echo function

src/str.rs

@@ -29,7 +29,7 @@ pub fn get_echo() -> Function {
         args: Args::Lazy(-1),
         function: Operation::Internal(
             |a: Ast, _b: Rc<RefCell<VTable>>, _c: Rc<RefCell<FTable>>| -> Ctr {
-                let mut string = String::from("echo");
+                let mut string = String::from("");
                 if !circuit(a, &mut |arg: &Ctr| {
                     match arg {
                         // should be a thing here