Crash while editing a show rule

[UserTeemu]

Environment

• Typstudio v0.1.0-dev.32
• Windows 10
• Typst CLI is also installed

Steps to reproduce

1. Open Typstudio and create a project with the following main.typ file:

#let kilometer = math.upright("km")
#let hour = math.upright("h")

#show math.equation: it => {
    it.body.fields()
}

The plane is traveling at the velocity of $2 (kilometer)/hour$

2. Highlight ".fields()" on line 5.
3. Press backspace.
4. Press backspace again (to try remove the y).
5. Crash!

https://github.com/Cubxity/typstudio/assets/20520700/aba38b3c-8df2-4d27-859c-952a3cfdbf04