Support different target paths when switching languages

[s3xysteak]

A example directory structure like:

- A
  - functions.ts
  - index.md
  - index-zh.md  
- B
  - functions.ts
  - index.md
  - index-zh.md

config.ts :

locales: {
  root: { 
    lang: 'en-US', 
    themeConfig: { 
      sidebar: [
        { link: 'A/index.md' }
      ]
    }
  },
  zh: { 
    lang: 'zh-Hans', 
    themeConfig: { 
      sidebar: [
        { link: 'A/index-zh.md' }
      ]
    }
  }
}

Obviously, it will causing errors because of the route. So I rewrite that:

rewrites: {
  ':module/index-zh.md': 'zh/:module/index.md'
}

But it still cause problem that the route becomes like: zh/A/. It seems that vitepress cannot find the file on the path.

[s3xysteak]

Rewrite to the :module will solve the problem.

rewrites: {
  // ':module/index-zh.md': 'zh/:module/index.md'
  ':module/index-zh.md': 'zh/:module.md'
}