Deprecate two-argument overload of HTMLCollection.item.

The single-argument version inherited from DOMList is correct. See https://dom.spec.whatwg.org/#htmlcollection

Author: danielnixon

src/main/scala/org/scalajs/dom/raw/Html.scala

@@ -1310,6 +1310,7 @@ abstract class HTMLCollection extends DOMList[Element] {
  *
  * MDN
  */
+ @deprecated("Non-standard.", "forever")
  def item(nameOrIndex: js.Any = js.native,
  optionalIndex: js.Any = js.native): Element = js.native