Missing Information about Default Prop Values in React Documentation

In a previous version of the React documentation, there was information about how props default to "true" if no value is passed (https://legacy.reactjs.org/docs/jsx-in-depth.html#props-default-to-true).
However, this information is missing in the current documentation. This can be confusing for developers who are new to React and may not be aware of this behavior. Please add this information back to the documentation to ensure consistency and clarity.

先閱讀 https://legacy.reactjs.org/docs/jsx-in-depth.html#props-default-to-true 中的「JSX in Depth」章節，然後在目前的 React 文件中搜尋對應的 JSX props 指引。當目前的文件說明沒有明確值的 prop 預設為 true，並為初學者清楚呈現這項行為時，即表示完成。