Custom syntax highlighting XML file

[gtheler]

The piece of software I'm trying to publish reads a certain input file, and the paper shows some snippets of sample input files.
Being able to generate a PDF with syntax highlight would increase the clearness of the paper.

I tried to add

syntax-definition: feenox.xml

in the YAML block of paper.md (and added feenox.xml in the same directory as paper.md) but it does not work as expected.
Cloning the repository locally, the only way to make it work was to modify the makefile to add

--syntax-definition=$(OPENJOURNALS_PATH)/feenox.xml

to the invocation of pandoc.

Would it be possible to have this custom highlighting XML in JOSS in the automated builds?