Line Highlighting in Code Blocks breaks in v0.19.2

[blurgyy]

Describe the bug

The line highlighting features are broke now in the official vitepress documentation: https://vitepress.vuejs.org/guide/markdown.html#line-highlighting-in-code-blocks

Reproduction

Open https://vitepress.vuejs.org/guide/markdown.html#line-highlighting-in-code-blocks and discover the lines are not highlighted:

Can also be reproduced locally with:

$ mkdir vtprs && cd vtprs
$ yarn init
$ yarn add --dev vitepress

Write some code blocks with lines highlighted in docs/index.md, like

```toml{2}
[highlight]
not_highlighted = true
public = false
```

run yarn vitepress dev docs and discover that second line is not highlighted as expected.

Expected behavior

Code lines are highlighted with minimal setup.

System Info

System:
    OS: Linux 5.14 Arch Linux
    CPU: (16) x64 Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz
    Memory: 5.12 GB / 15.49 GB
    Container: Yes
    Shell: 5.8 - /usr/bin/zsh
  Binaries:
    Node: 14.17.4 - /sbin/node
    Yarn: 1.22.15 - /sbin/yarn
    npm: 7.24.2 - /sbin/npm
  Browsers:
    Chromium: 94.0.4606.71
    Firefox: 93.0
  npmPackages:
    vitepress: ^0.19.2 => 0.19.2

Additional context

No response

Validations

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• Read the docs.
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