Add wide character formatting and output support to wincolor_sink. (#3092)

Fixes printing of unicode characters to the windows console such as microsecond suffix for std::chrono types.

include/spdlog/sinks/wincolor_sink-inl.h

@@ -134,9 +134,18 @@ void SPDLOG_INLINE wincolor_sink<ConsoleMutex>::print_range_(const memory_buf_t
                                                              size_t start,
                                                              size_t end) {
     if (end > start) {
+#if defined(SPDLOG_UTF8_TO_WCHAR_CONSOLE)
+        wmemory_buf_t wformatted;
+        details::os::utf8_to_wstrbuf(string_view_t(formatted.data() + start, end - start),
+            wformatted);
+        auto size = static_cast<DWORD>(wformatted.size());
+        auto ignored = ::WriteConsoleW(static_cast<HANDLE>(out_handle_), wformatted.data(), size,
+            nullptr, nullptr);
+#else
         auto size = static_cast<DWORD>(end - start);
         auto ignored = ::WriteConsoleA(static_cast<HANDLE>(out_handle_), formatted.data() + start,
                                        size, nullptr, nullptr);
+#endif
         (void)(ignored);
     }
 }