Error using divider with `---`

[oliveirarafa]

I'm using frontmatter in my Markdown and using dividers (---) within my text. However, the library is removing all the text between the --- tags.

I noticed there's a pull request (https://github.com/quantizor/markdown-to-jsx/pull/538) that automatically removes YAML frontmatter. I suspect this PR is causing the issue by removing all text between --- tags, and since my text contains two such dividers, it gets removed.

Using another type of divider tag (like *** or ___) works correctly.