Searching API needs better documentation

[denisrosset]

We state

  /** Performs a binary search, returns an index using the same convention as java.util.Arrays.binarySearch. */
final def search[@sp A: Order](as: Array[A], item: A, lower: Int, upper: Int): Int = {

However, our convention is to search the interval [lower, upper] inclusive, whereas java.util.Arrays.binarySearch excludes the upper bound.