test: update tests

ds-test/unicode-strings.c

@@ -12,15 +12,15 @@ int main(void)
 	printf("len: %zu\n", b_string_get_size(str, B_STRLEN_NORMAL));
 	printf("codepoints: %zu\n", b_string_get_size(str, B_STRLEN_CODEPOINTS));
 
-	b_string_iterator it;
 	const char *delims[] = {"в"};
 	size_t nr_delims = sizeof delims / sizeof delims[0];
 
-	b_string_tokenise(str, delims, nr_delims, 0, &it);
-	while (b_string_iterator_is_valid(&it)) {
-		printf("%s\n", it.string_value);
-		b_string_iterator_next(&it);
+	b_iterator *it = b_string_tokenise(str, delims, nr_delims, 0);
+	b_foreach(const char *, tok, it)
+	{
+		printf("%s\n", tok);
 	}
+	b_iterator_unref(it);
 
 	return 0;
 }