k_smallest: Clarify what happens when self.len() < k
@@ -2289,7 +2289,8 @@ pub trait Itertools : Iterator {
/// Sort the k smallest elements into a new iterator, in ascending order.
///
/// **Note:** This consumes the entire iterator, and returns the result
- /// as a new iterator that owns its elements.
+ /// as a new iterator that owns its elements. If the input contains
+ /// less than k elements, the result is equivalent to `self.sorted()`.
///
/// This is guaranteed to use `k * sizeof(Self::Item) + O(1)` memory
/// and `O(n log k)` time, with `n` the number of elements in the input.
