一个简单的库，用于方便地将值钳制在指定范围内。
let clamped1 = 25.clamped(to: 0...12) // = 12
let clamped2 = 10.clamped(to: 0...12) // = 10
let clamped3 = -10.clamped(to: 0...12) // = 0
let clamped4 = 25.clamped(to: 50...) // = 50
let clamped5 = 60.clamped(to: 50...) // = 60
let clamped6 = 25.clamped(to: ...50) // = 25
let clamped7 = 60.clamped(to: ...50) // = 50