Updated mediawiki/extensions
Project: mediawiki/extensions/ContentTranslation  f5646ced3788455b1793f29728a9723f83af1433

Source selector: Get languages using API and improve selector

* Get the supported languages from the cxserver API.
* List the source and target languages in dropdowns.
* In the target languages dropdown show the supported language at the top
  and the other languages after them as disabled options.

Change-Id: I35b8a690769228635766137e75fa93949c1def0a