Data type are not typewriter-style font when using --highlight-style=monochrome

[chdemko]

The use of fvextra allows for the introduction of line breaks in code. However, it introduces a bug when using --highlight-style=monochrome: types are no longer in a typewriter-style font.

$ pandoc -o output.pdf --template=eisvogel.tex --highlight-style=monochrome
```c
int main(void) {return 0;}
```

This give this output.pdf when it should give correct.pdf.