fix IsIterableLike example code

[xuwei-k]

use IterableOps instead of IterableLike. IterableLike does not exists.

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scala> :paste
// Entering paste mode (ctrl-D to finish)

import scala.collection.Iterable
import scala.collection.generic.IsIterableLike

class ExtensionMethods[A, Repr](coll: IterableLike[A, Repr]) {
  def mapReduce[B](mapper: A => B)(reducer: (B, B) => B): B = {
    val iter = coll.toIterator
    var res = mapper(iter.next())
    while (iter.hasNext)
      res = reducer(res, mapper(iter.next()))
    res
  }
}
// Exiting paste mode, now interpreting.

       class ExtensionMethods[A, Repr](coll: IterableLike[A, Repr]) {
                                             ^
On line 4: error: not found: type IterableLike

use iterator instead of toIterator

scala/src/library/scala/collection/IterableOnce.scala

Lines 80 to 81 in d94d9bc

	@deprecated("toIterator has been renamed to iterator", "2.13.0")
	@`inline` def toIterator: Iterator[A] = it.iterator