slice.Sum should be (more) generic

[timrprobocom]

slice.Sum is a very useful addition to the toolkit, but I don't understand why you have it returning a float. Wouldn't it be better if the return type matched the type of the slice elements? As it is, you have the potential to lose bits if the slice is int64.

https://github.com/dablelv/cyan/blob/6263b97ab9c2185800674db169ff99a30e958005/slice/get.go#L198C1-L207C1

For example:

func Sum[S ~[]E, E numerical](s S) E {
	var sum E
	for _, v := range s {
		sum += E(v)
	}
	return sum
}