boost::text::v1::to_title
// In header: <boost/text/case_mapping.hpp> template<code_point_iter I, std::sentinel_for< I > S, std::weakly_incrementable O, typename NextWordBreakFunc = next_word_break_callable> case_mapping_result< I, O > to_title(I first, S last, O out, case_language lang = case_language::other, NextWordBreakFunc next_word_break = NextWordBreakFunc{});