Pagedown: data-icon attribute for section header not working in html_resume

[everdark]

The section template Education {data-icon=graduation-cap data-concise=true} doesn't change the icon at all. Upon looking into the resulting html, it seems that the attributes (both data-icon and data-concise) are never respected at all.

Here is a minimum reproducible .Rmd:

````

title: "Test"
output:
pagedown::html_resume:
self_contained: true

knit: pagedown::chrome_print

Main

Test {#title}

Education {data-icon=graduation-cap data-concise=true}

````

In the resulting html (partial only):

<div id="main" class="section level1">
--
  | <h1>Main</h1>
  | <div id="title" class="section level2">
  | <h2>Test</h2>
  | </div>
  | <div id="education" class="section level2">
  | <h2>Education</h2>
  | </div>
  | </div>

The education div should have data-icon and data-concise attributes but it doesn't.
If we manually add the attribute back, the html will correctly change the default bookmark icon to the graduation-cap.

My system information:

R version 3.6.2 (2019-12-12)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 18363)

Matrix products: default

locale:
[1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252 LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
 [1] compiler_3.6.2  htmltools_0.4.0 tools_3.6.2     yaml_2.2.1      Rcpp_1.0.3      rmarkdown_2.1  
 [7] knitr_1.28      pagedown_0.8.1  xfun_0.12       digest_0.6.23   rlang_0.4.4     evaluate_0.14 

Additionally:

> rmarkdown:::pandoc_version()
[1] ‘2.8.0.1’

[RLesur]

Thanks a lot for the very detailed report!
It helped me a lot to identify this bug is similar to https://github.com/rstudio/rmarkdown/issues/1723 (this is a consequence of https://github.com/jgm/pandoc/issues/5965 introduced in Pandoc 2.8). You need to upgrade to Pandoc 2.9.

Please, note that rmarkdown does not support Pandoc 2.8.x, see the changelog for rmarkdown 2.1.

[everdark]

I've confirmed the issue can be fixed after I upgrade to Pandoc 2.9. Thx!