Clean up CSS and JS

* Pass css selector to prependTo() instead of constructing the
  object manually only to have jQuery make a clone of it.
  Either use $(selector).prepend() or prependTo(selector), doing
  both creates additional objects for no reason.

* Use .eq(i) instead of weird double-constructor pattern:
  > $( $( '#p-lang .body ul' )[1] )
  I've never seen this before and no idea where this pattern
  originates from or why anyone would do that.

* Minor style changes to improve readability and conformance
  with MediaWiki coding style:
  - Indent chained methods calls (firstly for consistency,
    secondly because one could argue it makes it clearer which
    statements are siblings and which are continued statements,
    and clarifies how many arguments are passed to a method)
  - Avoid trailing line comments.

* Remove slash from element creation construction. $() tags
  a tag description (to create an element from) or valid html
  to parse using the parser. <a/> is neither valid html (<a></a>)
  nor a simple tag (<a>). It works due to fault tolerance, but
  is considered bad practice.

* Add .jshintrc file to avoid error for undefined jQuery/mediaWiki.

Per https://www.mediawiki.org/wiki/CC/JS

Change-Id: Ibbb5c2db7865b43e6625aaa9a49fde5d8cb7cbe9