feat: circular slice selection

[victorguarana]

Adds two functions to select item by index of a slice as if it were a circular linked list.
The difference between them is in the way they treat an empty slice, CircularSelection returns an empty instance while CircularSelect panics.
I belive CircularSelection is better, feel free to comment too.

[samber]

Instead of adding a new helper, I would update the lo.Nth helper, to add your % operation.

However, for selecting a range of items, I would not change lo.Slice. Instead, I would create a new helper named lo.Circular or lo.Ring, that extracts a window with offset reset.

WDYT ?

[victorguarana]

But updating the lo.Nth operation with % would change its behavior. Because it would no longer return an error when the index is greater than the collection length.

Taking advantage of your idea, do you think it would be a good idea to rename the method to lo.Circular and move it to the find.go file?

[victorguarana]

@samber Changes ready. Can you check if it's ok now?