improved the docs and test cases

libraries/stdlib/src/kotlin/JLangIterables.kt

@@ -157,7 +157,7 @@ public inline fun <T, K> java.lang.Iterable<T>.groupBy(result: Map<K, List<T>> =
  * If a collection could be huge you can specify a non-negative value of *limit* which will only show a subset of the collection then it will
  * a special *truncated* separator (which defaults to "..."
  *
- * @includeFunctionBody ../../test/CollectionTest.kt appendString
+ * @includeFunctionBody ../../test/CollectionTest.kt makeString
  */
 public inline fun <T> java.lang.Iterable<T>.makeString(separator: String = ", ", prefix: String = "", postfix: String = "", limit: Int = -1, truncated: String = "..."): String {
     val buffer = StringBuilder()