Citations from parts defined in the frontmatter do not render

[fwkoch]

Description

If you have a citation in the frontmatter, something like:

---
title: My Paper
abstract: |-
  My abstract. See citation [paper](doi:10.1126/sciadv.abl4354).
---

it will not render in the site build. The mdast is transformed correctly, but the citation is not added to the references list in the page data. This is likely a very similar issue to https://github.com/jupyter-book/mystmd/issues/1602

Current Workaround

For now, you can get around this issue by defining the abstract in the body of your document:

---
title: My Paper
---

# Abstract

My abstract. See citation [paper](doi:10.1126/sciadv.abl4354).

Though this is not ideal, especially for other parts besides abstract, which are not as easy to define in the body.