Highlight only works with Ziggy out of the box

[rodolpheh]

Zine Version

0.11.2

Steps to Reproduce

Initialize a new Zine and add a code block for a language other than Ziggy:

```c
#include <stdio.h>
int main() {
   printf("Hello, World!");
   return 0;
}
``` 

Describe the issue

The syntax of the resulting HTML isn't highlighted. My understanding is that although languages are parsed into the right HTML classes, there is no colours because highlight.css only implements colours for Ziggy. Is there an highlight.css file that provides default colours for every languages or does this have to be manually added?

Additionally, is there a standard format to define colour schemes that we could use to generate a highlight.css to be used in Zine?

Happy to provide any help if it is within my skills.