Explain the problem.
Good day team. There is an issue where HTML classes are being mistakenly removed when specifying the language in inline code attributes. I tested this compiling pandoc-cli on the tip commit of main, which at the moment of this writing is the commit with hash 675e0c450. Let me show you an example:

`def func1():`{.class1 .my-type .pristine .python}

How should this piece of Markdown be rendered as HTML? According to the manual, it should include at least the 4 classes: ".class1 .my-type .pristine .python", alas, it only contains 1 class, the language one: ".python". Here is how it looks on https://pandoc.org/try/

If we now remove the language class ".python", then the other 3 classes do appear in the HTML representation as expected, you can see the 'class1' being highlighted on both the Markdown and HTML displays:

Steps to replicate

1. Run the following command:

pandoc -f markdown -t html
`def func1():`{.class1 .my-type .pristine .python}
^D

Observed behavior

This is the output received from that command, the three classes ".class1 .my-type .pristine" are missing:

<p><code
class="sourceCode python"><span class="kw">def</span> func1():</code></p>

Expected behavior

The three classes should appear in the ouput, potentially like the following:

<p><code
class="sourceCode python class1 my-type pristine"><span class="kw">def</span> func1():</code></p>

Pandoc version?
This was tested on the tip of the main branch, which is 675e0c450 (HEAD -> main, origin/main, origin/HEAD) MANUAL.txt: Small rewrite of syntax-highlighting info. at the moment of this writing.

Thank you for your attention to this issue.