Triple backticks inside strings inside a code block will bork highlighting

### Bug description

``````
```{r}

"
```
```
"

```
``````

Results in

<img width="250" alt="Image" src="https://github.com/user-attachments/assets/90e58810-cb47-4896-9c1f-802436c837fc" />

### Steps to reproduce

_No response_

### Actual behavior

_No response_

### Expected behavior

_No response_

### Your environment

_No response_