JSDuck-ify /resources/mediawiki.special/*

- Adds mw.special.recentchanges to the index.
- Adds mw.special.upload to the index.
- Register File as valid value type. Relates to the
  "File" interface (from HTML5 File APIs; http://dev.w3.org/2006/webapi/FileAPI/#dfn-file)
- Sort directories in jsduck/config.json alphabetically.

Change-Id: I282cbeeec60b9f527879aedd90ba824a833438b7