message: Fix typo in assert
diff: @@ -90,7 +90,7 @@ void read_number(state<Iterator, Sentinel>& ps, Consumer& consumer) {
  });
  // Switches from parsing an integer to parsing a double.
  auto ch_res = [&](result_type_t x) {
  - CAF_ASSERT(result_type = integer);
  + CAF_ASSERT(result_type == integer);
  result_type = x;
  // We parse doubles as positive number and restore the sign in `g`.
  dbl_res = result_type == negative_double
  