Autolinking Quarto html remove the "copy-code" button

The copy-code button is removed when running downlit on html pages created by Quarto. This happens because downlit seems to replace any class of the DIV, instead of appending to it (

downlit/R/downlit-html.R

Line 54 in 4011b2f

pre_class = "downlit sourceCode r",

).

Here is a reprex. The "test.html" file will have a copy-code button, but "downlit-test.html" will not:

qmd_lines <- c(
  "---", "title: test", "---", "", "```{r}", "mtcars", "```"
)
writeLines(qmd_lines, "test.qmd")
quarto::quarto_render("test.qmd")
#> �[31m
#> 
#> processing file: test.qmd
#> �[39m  |                                                                              |                                                                      |   0%  |                                                                              |.......................                                               |  33%
#>   ordinary text without R code
#> 
#>   |                                                                              |...............................................                       |  67%
#> label: unnamed-chunk-1
#>   |                                                                              |......................................................................| 100%
#>   ordinary text without R code
#> 
#> 
#> �[31moutput file: test.knit.md
#> 
#> �[39m�[1mpandoc �[22m
#>   to: html
#>   output-file: test.html
#>   standalone: true
#>   section-divs: true
#>   html-math-method: mathjax
#>   wrap: none
#>   default-image-extension: png
#>   
#> �[1mmetadata�[22m
#>   document-css: false
#>   link-citations: true
#>   date-format: long
#>   lang: en
#>   title: test
#>   
#> Output created: test.html

downlit::downlit_html_path("test.html", "downlit-test.html")

^{Created on 2022-08-05 by the reprex package (v2.0.1)}

This is taken care of in #155

Awesome, thanks!

@edgararuiz For information, the PR I made turned out to be wrong.