fix(_comp_count_args): ignore empty $3

Author: akinomyoga

bash_completion

@@ -2193,7 +2193,7 @@ _comp_count_args()
     ret=1
     for ((i = 1; i < cword; i++)); do
         # shellcheck disable=SC2053
-        if [[ (${words[i]} != -?* || ${words[i]} == ${3-}) &&
+        if [[ (${words[i]} != -?* || ${3-} && ${words[i]} == ${3-}) &&
             ${words[i - 1]} != ${2-} ]]; then
             ((ret++))
         elif [[ ${words[i]} == -- ]]; then