refactor(typst): improve terms accessibility

[mcanouil]

Refactor the terms display in Typst to enhance accessibility by using a more semantic structure.

The current code basically reconstruct the list making it fail UA-1 accessibility check from Typst 0.14.

The new rule is simpler, keep the structure of the list.
it also add an explicit breakable: false to ensure definition and term stay together.

For reference, the current Typst check error:

#set document(title: "Demo Document")

#show terms: it => {
  it
    .children
    .map(child => [
      #strong[#child.term]
      #block(inset: (left: 1.5em, top: -0.4em))[#child.description]
    ])
    .join()
}

/ term: #block[
    definition
  ]

typst compile demo.typ --pdf-standard=ua-1

error: PDF/UA-1 error: invalid list (L) structure
   ┌─ demo.typ:13:2
   │
13 │ / term: #block[
   │   ^^^^
   │
   = hint: list (L) may not contain paragraph (P)
   = hint: this is probably caused by a show rule

error: PDF/UA-1 error: invalid list (L) structure
   ┌─ demo.typ:13:0
   │  
13 │ ╭ / term: #block[
14 │ │     definition
15 │ │   ]
   │ ╰───^
   │  
   = hint: list (L) may not contain marked content directly
   = hint: this is probably caused by a show rule

[jgm]

A more direct way to reproduce the issue:

% pandoc -t typst -o my.pdf  --pdf-engine-opt='--pdf-standard=ua-1'
term

:    definition
^D
error: PDF/UA-1 error: invalid list (L) structure
    ┌─ toPdfViaTempFile51510-0.typ:152:2
    │
152 │ / term: #block[
    │   ^^^^
    │
    = hint: list (L) may not contain paragraph (P)
    = hint: this is probably caused by a show rule

error: PDF/UA-1 error: invalid list (L) structure
    ┌─ toPdfViaTempFile51510-0.typ:152:0
    │  
152 │ ╭ / term: #block[
153 │ │ definition
154 │ │ ]
    │ ╰─^
    │  
    = hint: list (L) may not contain marked content directly
    = hint: this is probably caused by a show rule

Error producing PDF.

[jgm]

But I don't yet understand what is wrong with what we're doing now.
List may not contain Paragraph? But certainly in general lists do contain paragraphs, and no error is raised with e.g.

- one

  second paragraph

- two

[jgm]

Oh, I see, the list needs "items" as direct children and we were destroying that structure.

[mcanouil]

Oh, I see, the list needs "items" as direct children and we were destroying that structure.

Yes, that's it.