Introduce theorem variation for axioms

[luifrancgom]

Description

I would like to know if you can consider adding a theorem variation for axiom, as described in #13194 , given that it is not currently listed in Theorems and Proofs.

I located the list where the various theorem types are defined by following the guidance in #3640 (src/resources/filters/customnodes/theorem.lua) By adding the following entry after alg, I was able to introduce the new type:

axm = {
    env = "axiom",
    style = "plain",
    title = "Axiom"
  }

I tested this in the development version with:

---
title: My title
format: 
  html:
    embed-resources: true
  pdf:
    number-sections: true
  docx: default
  typst:
    number-sections: true
  odt: default
  epub: default
---

# My section

::: {#axm-extension}

## Axiom of extension

Two sets are equal if and only if they have the same elements.

:::

@axm-extension

The expected results were produced for all formats except for the reference label. For example, in the Typst format:

However, I was not able to determine where the reference labels are defined. I also did not fully understand the explanation in tests/docs/smoke-all/crossrefs/theorem/algorithm.qmd for #3640 , in order to reproduce the same result for an axiom variation. Rendering algorithm.qmd in the development version yielded the same result as in my case:

I am unsure how to change axm. to Axiom and where in the development version to make the necessary modifications so that I can also use the options described in Cross Reference Options.

[mcanouil]

Please search before opening new requests.

• [Feature Request] Add more theorem types from amsthm (e.g. axiom, assumption, ...) #3979