bug#68948: temp fix

[chris <chris@bumblehead.com>]

The following workaround can be used,
```
HLDIRS=$(guix build highlight); # returns two directories
HLDIR="${HLDIRS##*[[:space:]]}"; # returns the second dir, after whitespace
DATADIR="$HLDIR/etc/highlight/";
echo "(highlight (package bug))" | highlight --data-dir=$DATADIR -O xterm256 --syntax lisp
```

Based on my understanding, the current package definition is correct. Possibly a patch like this could resolve the issue the current package definition seems correct.
```
diff --git a/gnu/packages/pretty-print.scm b/gnu/packages/pretty-print.scm
index b95f56729a..2a7cf74009 100644
--- a/gnu/packages/pretty-print.scm
+++ b/gnu/packages/pretty-print.scm
@@ -389,7 +389,7 @@ (define-public highlight
                           (lambda* (#:key inputs outputs #:allow-other-keys)
                             (let* ((out (assoc-ref outputs "out"))
                                    (data (string-append out
-                                                        "/share/highlight/"))
+                                                        "/etc/highlight/"))
                                    (conf (string-append out "/etc/highlight/"))
                                    (doc (string-append out
                                          "/share/doc/highlight/"))
```