docs(zh): translate the currentRoute section of migration to Chinese

[gophlet]

Finished the translation of Migrating from Vue 2

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After:

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[gophlet]

关于原文中：

The currentRoute property is now a ref()

的翻译，我能想到的有两种译法：

1. currentRoute 属性现已使用 ref() 声明其响应式状态

2. currentRoute 属性现已支持 ref() 响应式

哪种会更好一些呢？