Function subtract

subtract(y: number): ((x: number) => number)
Example
```
import * as N from "flurp/number";

const subtractFive = N.subtract(5);
subtractFive(2);       // -3
```
Parameters
- y: number
Returns ((x: number) => number)
- - (x: number): number
  - Parameters
    - x: number
    Returns number
- Defined in src/number.ts:427