title: Space after every five rows in kable output (with booktabs option) in R Markdown document
body: <p>I am using <code>knitr::kable()</code> to render tables as part of an <strong>R Markdown</strong> document (that itself is part of a <strong>bookdown</strong> project). In particular, the booktabs option (through setting the <code>booktabs</code> argument to equal <code>TRUE</code>) renders the table in a nice-looking way. However, I'd like for there not to be a space after every five rows.</p>
  
  <p>Here, for example, is the code and how the table in the bookdown demo appears when rendered as a PDF:</p>
  
  <pre><code>knitr::kable(
    head(iris, 20), caption = 'Here is a nice table!',
    booktabs = TRUE
  )
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/FTmvt.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FTmvt.png" alt="iris table with booktabs"></a></p>
  
  <p>I'd like for the space that aappears after every five rows to not be included, but I cannot seem to find a setting in <code>knitr::kable()</code> that does this. </p>