Function clamp

clamp(a?, b?): Mapper<number>
Clamps x to range [a, b].
Parameters
- a: number = 0
  Minimum range value.
- b: number = 1
  Maximum range value.
Returns Mapper<number>
Example
```
clamp()(0.2);
// ⮕ 0.2

clamp()(-2);
// ⮕ 0.5

clamp(5, 10)(33);
// ⮕ 10
```