Admonition Markdown Extension for RMarkdown (MkDocs)

I'm interested in using Admonition in my Rmarkdown documents for prettier documentation. Any ideas on how to use markdown extensions like this?

For text or graphics, the Tufte template provides sidenotes.. At the other end of the spectrum, pdf-output with LaTeX provides features limited only by the author's patience in coding. For Admonition, you would have to use RStudio as a Python IDE or reverse engineer their template and logic.