title: How to review the outline of `.rmd` file in vs code?
body: <p><a href="https://i.stack.imgur.com/Fm4x5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Fm4x5.png" alt="enter image description here" /></a></p>
  <p>I know vs code has ability to review ouline of <code>markdown</code>.<br />
  As to Rmarkdown with knitr,*.rmd files,how to review outline?</p>