Fix typst-show.typ

[Jarartur]

I don't know if this is the correct way but I've been getting errors like this:

[typst]: Compiling IEEEVR-Poster.typ to IEEEVR-Poster.pdf...error: expected integer, boolean, float, or string, found content
    ┌─ \\?\C:\Users\arjur\Documents\Projects\IEEEVR-Poster\IEEEVR-Poster.typ:254:30
    │
254 │   footer_text_font_size = int(footer_text_font_size) * 1pt
    │                               ^^^^^^^^^^^^^^^^^^^^^

help: error occurred in this call of function `poster`
    ┌─ \\?\C:\Users\arjur\Documents\Projects\IEEEVR-Poster\IEEEVR-Poster.typ:378:14
    │  
378 │   #show: doc => poster(
    │ ╭───────────────^
379 │ │    title: [This is an academic poster with typst and quarto!], 
380 │ │   // TODO: use Quarto's normalized metadata.
381 │ │    authors: [A. Smith, B. Jones, C. Brown, D. Miller], 
    · │
436 │ │   doc,
437 │ │ )
    │ ╰─^

This was solved by deleting [] surrounding $footer-text-font-size$ on line 71.