map() for float data type

If a `float` argument is passed to the `map()` function, it truncates them to integer values. This provides erroneous output that may not be immediately noticed. This does not produce a compiler warning.

Please add a `float` variant of `map()`:

```cpp
float mapf(float value, float istart, float istop, float ostart, float ostop) {
return ostart + (ostop - ostart) * ((value - istart) / (istop - istart));
}
```

### Additional context

#### Additional reports

- https://dicks-photon-arduino.blogspot.com/2016/05/40-arduino-c-map-function-vs.html

#### Related

- https://github.com/arduino/Arduino/issues/288

首先在 ArduinoCore-API 中找到现有的 map() 入口点，并检查它如何处理数值输入和输出。当针对 float 的映射 API 能够保留 float 参数的小数值，同时保持现有 map() 行为不变时，即视为完成。

由索引模型根据 Issue 内容生成。