Is your feature request related to a problem? Please describe.

In many cases, developers will provide code groups for multiple programming languages at the same time. I hope that after the user switches one, other code groups can automatically follow, and it is best to be persistent.

#2773, a solution is proposed here, but I don't think it's good enough

1. Only supports tab, but code group needs it more
2. This is a very commonly used feature, I think it should be officially supported, not by a plugin

Describe the solution you'd like

::: code-group

```js [config.js] :js <-- key
const config = {
// ...
}

export default config
```

```ts [config.ts] :ts
import type { UserConfig } from 'vitepress'

const config: UserConfig = {
// ...
}

export default config
```

:::

Describe alternatives you've considered

No response

Additional context

No response

Validations

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