rubico/x/endsWith

```coffeescript
endsWith(suffix string)(value string) -> boolean
```
Determine whether a string ends with a suffix.

```javascript
console.log(endsWith('y')('hey')) // true
```

The issue is to implement an `endsWith` function in the rubico library. Look at the x/ directory for existing utility functions, likely in a file like `x/endsWith.js`. The function should take a suffix string and return a function that takes a value string, returning a boolean. Check the library's testing setup to write a test for the new function, ensuring it matches the example: endsWith('y')('hey') returns true.

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