* In mw.uls.addPreviousLanguage, jQuery.map was used for what is
essentially filtering, not mapping. Filtering was used to remove
one element from array. Use Array.prototype.splice instead.
* In mw.uls.getFrequentLanguageList, replace:
- jQuery.each with Array.prototype.forEach
- jQuery.inArray with Array.prototype.indexOf
- jQuery.grep with Array.prototype.filter
Change-Id: Id2208b3c89e982f91f49981d18e588ae8ce3b130