title: How to show kable kableExtra tables in R Markdown notebook, not just in the knitted doc?
body: <p>I've been using <code>kable</code> and <code>kableExtra</code> to good effect, and have been creating tables that then display in-line in the R Markdown notebook (as well as knitting to html). Now, this morning I re-installed R and RStudio... and now the tables only appear in the viewer pane and I get this weird code in-line as output -</p>
  
  <pre><code>&lt;table class="table table-striped" style="width: auto !important; margin-left: auto; margin-right: auto;"&gt;
   &lt;thead&gt;
    &lt;tr&gt;
     &lt;th style="text-align:left;"&gt;   &lt;/th&gt;
  </code></pre>
  
  <p>[<em>this goes on for many lines</em>]</p>
  
  <p>It does still work when knitting, it's just annoying that it's showing this in-line instead of the table. Interestingly, it <em>does</em> seem to show the table when I just call <code>kable</code>, but it seems like it's <code>kableExtra</code> that isn't liking it.</p>
  
  <p>I've updated the packages, manually uninstalled and then reinstalled the packages, and even completely removed R and R Studio before installing them from scratch.
  I'm sure that it's not my code that is the problem, because it's doing this even for a data script that I haven't modified and which was working perfectly yesterday.</p>
  
  <p>Here is a reproducible example using the <code>mtcars</code> dataset. I think this would need to be run in an R Markdown Rmd file, to show the problem I'm facing.</p>
  
  <pre><code>library(tidyverse)
  library(knitr)
  library(kableExtra)
  
  df &lt;- head(mtcars)
      kable(df, format = "html", digits = 2) %&gt;%
              kable_styling(bootstrap_options = "striped", full_width = F)
  </code></pre>
  
  <p>This is actually one of the examples used in the <code>kableExtra</code> documentation - and to repeat - the code is working when knitting to html, it just isn't showing in the actual document anymore, and it was yesterday.</p>
  
  <p>Any advice greatly appreciated.</p>