Feature request: re-expose subslide counter

[Vtec234]

Thanks for all your work on this package, it is great! Unfortunately, since version 0.4.0 it seems to have become harder to have content using other packages appear dynamically. Specifically, in polylux 0.3.1 one could easily generate dynamic CeTZ diagrams like so:

context cetz.diagram({
  if 2 <= logic.subslide.get().last() {
    // draw some stuff
  }
})

This counter has been hidden in 0.4.0, so I no longer know how to do this. The feature request is thus for a mechanism for doing the above which is as general as directly accessing the counter (only, uncover, etc don't seem to work because they only take Typst content). In particular, re-exporting logic.subslide would work.

[andreasKroepelin]

Does this apply? #158 (comment)

[Vtec234]

#alternatives-fn does it. Thank you!