Add sample for Map.flatMap

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

@@ -40,7 +40,7 @@ public fun <K, V> Map<out K, V>.toList(): List<Pair<K, V>> {
 /**
  * Returns a single list of all elements yielded from results of [transform] function being invoked on each entry of original map.
  * 
- * @sample samples.collections.Collections.Transformations.flatMap
+ * @sample samples.collections.Maps.Transformations.flatMap
  */
 public inline fun <K, V, R> Map<out K, V>.flatMap(transform: (Map.Entry<K, V>) -> Iterable<R>): List<R> {
     return flatMapTo(ArrayList<R>(), transform)

libraries/stdlib/samples/test/samples/collections/maps.kt

@@ -353,7 +353,11 @@ class Maps {
             assertPrints(peopleToAge.map { it.value }, "[20, 21]")
         }
 
+        @Sample
+        fun flatMap() {
+            val map = mapOf("122" to 2, "3455" to 3)
+            assertPrints(map.flatMap { (key, value) -> key.take(value).toList() }, "[1, 2, 3, 4, 5]")
+        }
     }
-
 }