KT-20357 Add sortedBy() sample (#3283)

libraries/stdlib/common/src/generated/_Sequences.kt

@@ -533,6 +533,8 @@ public fun <T : Comparable<T>> Sequence<T>.sorted(): Sequence<T> {
  * The sort is _stable_. It means that equal elements preserve their order relative to each other after sorting.
  *
  * The operation is _intermediate_ and _stateful_.
+ * 
+ * @sample samples.collections.Collections.Sorting.sortedBy
  */
 public inline fun <T, R : Comparable<R>> Sequence<T>.sortedBy(crossinline selector: (T) -> R?): Sequence<T> {
     return sortedWith(compareBy(selector))