The cppreference page for transform_view has the following code example:
auto show = [](const unsigned char x) { std::putchar(x); };
std::string in{ "cppreference.com\n" };
std::ranges::for_each(in, show);
std::ranges::for_each(in | std::views::transform(rot13), show);
The last line confuses me. What does in | std::views::transform(rot13) mean? Neither the page for transform_view nor the basic_string page define an operator|.
