bug#68948: highlight error, cannot open filetypes.conf: No such file or directory

[chris]

There is an issue using "highlight"

https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/pretty-print.scm#n353
http://www.andre-simon.de/doku/highlight/en/highlight.php#ch3_8

This unexpected error is reproduced easily with the command below: "cannot open 
filetypes.conf"
```
$ echo "(highlight (package bug))" | highlight -O xterm256 --syntax lisp
cannot open filetypes.conf: No such file or directory
(highlight (package bug))
```

Creating `~/.highlight/filetypes.conf` did not resolve the error.
Setting "HIGHLIGHT_DATADIR=$HOME/.config/highlight/" did not resolve the error.

Any advice is welcome. Thank you :)

Chris