games/punchy: unbreak build with libc++ 19

In file included from ../../../punchy-0.3.0/cargo-crates/v8-0.47.1/v8/src/inspector/v8-string-conversions.cc:5:
In file included from ../../../punchy-0.3.0/cargo-crates/v8-0.47.1/v8/src/inspector/v8-string-conversions.h:8:
/usr/include/c++/v1/string:820:42: error: implicit instantiation of undefined template 'std::char_traits<unsigned short>'

820 |   static_assert(is_same<_CharT, typename traits_type::char_type>::value,
    |                                          ^

../../../punchy-0.3.0/cargo-crates/v8-0.47.1/v8/src/inspector/v8-string-conversions.cc:387:26: note: in instantiation of template class 'std::basic_string<unsigned short>' requested here

387 | std::basic_string<UChar> UTF8ToUTF16(const char* stringStart, size_t length) {
    |                          ^

/usr/include/c++/v1/__fwd/string.h:23:29: note: template is declared here

23 | struct _LIBCPP_TEMPLATE_VIS char_traits;
   |                             ^

Reported by: pkg-fallout
Obtained from: 2d0cb380eb97