Describe your feature request

GitLab uses “GitLab Flavored Markdown” (GFM). It extends the CommonMark specification (which is based on standard Markdown) in a few significant ways to add additional useful functionality. It was inspired by GitHub Flavored Markdown.

Missing extensions:

• Multiline blockquote: >>>\n%text%\n<<<
• Inline diff: { additions }, [ additions ], ...
• Inline math via $` ... `$
• Math using KaTeX via ```math code block
• Front matter: TOML ( ) and JSON (;;;)