fix(_comp_finalize): fix up f1f454b for nounset

Author: akinomyoga

bash_completion

@@ -860,7 +860,7 @@ _comp_finalize()
             fi
 
             # Call general finalizers
-            if ((${#BASH_COMPLETION_FINALIZE_HOOKS[@]})); then
+            if [[ ${BASH_COMPLETION_FINALIZE_HOOKS[*]+set} ]]; then
                 for _comp_local_hook in "${BASH_COMPLETION_FINALIZE_HOOKS[@]}"; do
                     eval -- "$_comp_local_hook"
                 done