fix checking hastags and nothas tags

cmd/pttodo-cli/cli.go

@@ -255,14 +255,14 @@ func dump(dry bool, writer io.Writer, filepath string, tags []string, search, ro
 		if len(tags) > 0 {
 			result := make([]pttodo.Todo, 0, len(todos))
 			for _, todo := range todos {
-				want := len(todo.Tags) > 0
+				skip := false
 				for _, tag := range tags {
 					positiveTag := strings.TrimLeft(tag, "-")
 					hasTag := strings.Contains(todo.Tags, positiveTag)
 					wantToHaveTag := !strings.HasPrefix(tag, "-")
-					want = want && (hasTag == wantToHaveTag)
+					skip = skip || !(hasTag == wantToHaveTag)
 				}
-				if want {
+				if !skip {
 					result = append(result, todo)
 				}
 			}