Adjustment to typst version 0.13.0

[joonas-si]

With the new typst release (0.13.0) chem-par produces the following error:

error: type state has no method display
┌─ @preview/chem-par:0.0.1\src\stateful.typ:6:34
│
6 │ Chemistry-Style-disable-state.display(bDisable =>{

Typst removed the .display method and replaced it with .get (see https://typst.app/docs/changelog/0.13.0/)

In my local environment I fixed it with changing the if-state-enabled function to this:

#let if-state-enabled( it , fn ) = context {
    if (Chemistry-Style-disable-state.get() == false){return it}
    return fn
}