Zensical relies on Pygments for syntax highlighting (zensical/zensical#775), and therefore inherits this limitation in Markdown code fences where yaml works but yml is not recognized.

Other syntax highlighters like Highlight.js, Prism.js, and Rouge already support yml as an alias, and GitHub Markdown also accepts yml for YAML code fences, so this is a common expectation in the ecosystem.

Example (GitHub Markdown-style):

name: example
on:
  push:
    branches: [main]

I am happy to open a PR for this if helpful.