Simplify the decimal point condition in dump_float

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/output/serializer.hpp

@@ -2106,7 +2106,7 @@ class serializer
         const std::size_t decimal_point_len = std::char_traits<char>::length(decimal_point);
 
         // convert decimal point to '.'
-        if (decimal_point_len != 0 && !(decimal_point_len == 1 && decimal_point[0] == '.'))
+        if ((decimal_point_len > 1) || (decimal_point_len == 1 && decimal_point[0] != '.'))
         {
             const auto first = number_buffer.begin();
             const auto last = first + len;