force new enums for pinMode and pinStatus to 8 bits type instead of default int

I've seen
```
typedef enum {
LOW = 0,
HIGH = 1,
CHANGE = 2,
FALLING = 3,
RISING = 4,
} PinStatus;

typedef enum {
INPUT = 0x0,
OUTPUT = 0x1,
INPUT_PULLUP = 0x2,
INPUT_PULLDOWN = 0x3,
} PinMode;
```

This will let the compiler decide how big the backend storage needs to be for those, and it will default to an int (16 or 32 bit depending on architecture). There is no need for this waste of memory and it prevents also some compiler optimization

I suggest forcing the uint8_t type, 256 values should be plenty to represent a pinMode or a pinStatus..

proposed changes:

```
typedef enum : uint8_t {
LOW = 0,
HIGH = 1,
CHANGE = 2,
FALLING = 3,
RISING = 4,
} PinStatus;

typedef enum : uint8_t {
INPUT = 0x0,
OUTPUT = 0x1,
INPUT_PULLUP = 0x2,
INPUT_PULLDOWN = 0x3,
} PinMode;
```

but in practice I would vote against getting these changes in production. There is no value added and tons of unwanted consequences for existing code out there to make this worthwhile.

首先找到 ArduinoCore-API API 中 PinMode 和 PinStatus 的 enum 声明，然后评估其对现有 Arduino 代码的源代码兼容性和二进制兼容性的影响。完成的要求是，项目需要决定所提议的底层类型 uint8_t 是否可接受；该 issue 本身不建议将其用于生产环境。

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