title: kableExtra: Change font size of table footnote
body: <p>I'd like for my font size in the footnotes to be smaller than the text in the table, but can't figure it out. Is there something similar to kable_styling where I can edit the text and color of rows in the table that can be used for footnotes? I am using RMarkdown to generate the HTML not LateX. </p>
  
  <p><a href="https://i.stack.imgur.com/nnPcC.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nnPcC.png" alt="enter image description here"></a></p>
  
  <pre><code>---
  title: "Untitled"
  output: html_document
  ---
  
  ```{r setup, include=FALSE}
  knitr::opts_chunk$set(echo = FALSE )
  
  library( kableExtra )
  library( knitr ) 
  
  ```
  
  ```{r mtcars}
  
   tab_mtcars &lt;- knitr::kable( mtcars[ 1:5 , c( 1:4 )] , format = "html", col.names = c( "MPG", "CYL", "DISP" , "HP" ) ,  align = "lccc" , escape = F ) %&gt;% kable_styling( full_width = T , bootstrap_options = c( "hover", "condensed" , "bordered"), position = "left") %&gt;% add_header_above( c( "mtcars example" = 5 ) , bold = TRUE ) %&gt;% footnote( general = c( "Here is the footnote where I would like font smaller than above" ),     general_title = "Note: ", footnote_as_chunk = T )
  
  ```
  
  `r tab_mtcars`
  </code></pre>