feat: 改进Value对象的显示格式，增加键值对输出

src/interpreter/mod.rs

@@ -44,7 +44,14 @@ impl fmt::Display for Value {
             Value::String(s) => write!(f, "{}", s),
             Value::Bool(b) => write!(f, "{}", b),
             Value::Nil => write!(f, "nil"),
-            Value::Object(_) => write!(f, "<object>"),
+            Value::Object(obj) => {
+                let obj = obj.borrow();
+                write!(f, "{{ ")?;
+                for (key, value) in obj.iter() {
+                    write!(f, "{}: {}, ", key, value)?;
+                }
+                write!(f, "}}")
+            },
             Value::Function(_) => write!(f, "<function>"),
             Value::NativeFunction(_) => write!(f, "<native function>"),
         }