cat-highlight: Fix error check

It caused cat-highlight to always return with an error status.

.config/zsh/functions/cat-highlight

@@ -50,5 +50,5 @@ done
 
 for file in ${files}; do
     eval "${catopen/\%s/${file}}" 2>& -
-    [[ ${?} -ne 0 ]] && \cat ${file}
+    [[ ${?} -eq 0 ]] || \cat ${file}
 done | \cat ${args}