Fix up various issues leading to bug 40780.

Fix up various issues leading to bug 40780.

* jquery.autoEllipsis didn't return 'this', which means whenever it
  was used in a chain, it would return undefined.

  So in mediawiki.searchSuggest append( ... autoEllipsis() ) would
  apply it to a detached node that stays detached because it
  isn't passed to append.

* Remove redundant passing of this in jQuery context to $().
  On jQuery.prototype, 'this' is obviously a jQuery object. In
  jquery.highlightText, which is called from jquery.autoEllipsis.

* Remove redundant .empty() call before calling .text( .. ),
  .text() replaces all content and naturally is forced to empty
  the element first.

* Merge use of $el and $container in jquery.autoEllipsis.js. They
  were both pointing to the same object, having two names was only
  confusing.

* Spaces.

Change-Id: I4649ec0c89d38c4d79d1dceec28227902cd48d32