match the grammar object with the end of the specified string
If the match is unsuccessful, then n is std::undefined.
| std::match | match the grammar object with the start of the specified string |
| std::search | search from the grammar object from the start or end of the specified string |
| std_types::character | matches the end of a string with the character |
| std_types::set | matches the end of a string with the set's characters |