Added NavigatorLanguage.languages

`NavigatorLanguage.languages` is the way to get value that is equiualent to
`Accept-Language` HTTP header in every HTTP request from the user's browser.

Docs: https://developer.mozilla.org/en-US/docs/Web/API/NavigatorLanguage/languages

Author: catap

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

@@ -5372,6 +5372,15 @@ trait NavigatorLanguage extends js.Object {
    * MDN
    */
   def language: String = js.native
+
+  /**
+   * Returns a Array of DOMStrings representing the the user's preferred languages.
+   * The language is described using BCP 47 language tags.
+   * The null value is returned when this is unknown.
+   *
+   * MDN
+   */
+  def languages: js.Array[String] = js.native
 }
 
 @js.native