message: updated fmt custom type formatter
diff: @@ -26,13 +26,13 @@ namespace fmt {
  char>> {
  // The following functions are not defined intentionally.
  template <typename ParseContext>
  - typename ParseContext::iterator parse(ParseContext &ctx) {
  + auto parse(ParseContext &ctx) -> decltype(ctx.begin()) {
  return ctx.begin();
  }
  template <typename FormatContext>
  auto format(const T &val, FormatContext &ctx) -> decltype(ctx.out()) {
  - return format_to(ctx.begin(), "{}", val.toString());
  + return format_to(ctx.out(), "{}", val.toString());
  }
  };
  } // namespace fmt
  