Horizontal rules interpreted as frontmatter

[Ell]

When using the single-file mode, multiple horizontal rules are erroneously interpreted as additional front matter and stripped, even when an actual front matter block is provided. Here's an example:

The markdown

---
title: "Test!"
---

This is

a test file

---

with some content in it

that is pretty cool

---

but without any frontmatter

exports to PDF as the following:

As you can see, the middle section is entirely ignored.

Of course, horizontal rules can still be used properly by using ___ or *** instead, but I personally prefer using --- since it's what I'm most used to.