pandoc-3.10: test/command/5540.md

```
% pandoc -f latex -t native
\begin{lstlisting}[language=myfunnylanguage]
Stay pure!
\end{lstlisting}
^D
[ CodeBlock
    ( ""
    , [ "myfunnylanguage" ]
    , [ ( "language" , "myfunnylanguage" ) ]
    )
    "Stay pure!"
]
```