[Typo]: Remove from menu for non-existent pages

Summary

I clicked on the menu because I was curious about the router, but the page was not provided.

Page

https://18.react.dev/learn/creating-a-react-app#react-router-v7

Details

I clicked on the menu because I was curious about the router, but the page was not provided.

If it's a non-existent page, I think it would be better if it wasn't shown at all in the menu.

I think it's a problem when I choose version 18, but not in version 19.
https://react.dev/learn/creating-a-react-app#react-router-v7

比较报告的 Creating a React App 页面中 React Router v7 链接附近的版本 18 和版本 19 文档菜单。确定指向不可用页面的菜单项，将其从版本 18 菜单中移除，并验证不存在的链接不再出现。