Leading whitespace in code blocks breaks all subsequent highlighted codeblocks

[EmNudge]

Describe the bug

If you have a leading white space in a codeblock, it will break the parser such that having subsequent highlighted codeblocks will crash the current slide.

This is an issue for assembly which often has leading whitespace. This is also where I encountered this problem.

Minimal reproduction

https://stackblitz.com/edit/github-sspw9v?file=slides.md=

block 1

```
 test
```

block 2

```js
const val = 42
```

Environment

• Slidev version: 0.49.29
• Browser: Chrome
• OS: MacOS