refactor(tar): remove redundant '\n' in command substitution

Author: akinomyoga

completions/tar

@@ -437,7 +437,7 @@ _comp_cmd_tar__try_list_archive()
                 while read -r line; do
                     printf "%q\n" "$(printf %q"\n" "$line")"
                 done
-        )" -- "$(printf "%q\n" "$cur")"))
+        )" -- "$(printf %q "$cur")"))
         return 0
     fi
 }