Minor tweaks to new pkg.uptodate state

2 minor changes:

1. Moved state function up above mod_init(). This is just for
   consistency across the codebase, mod_init() typically just appears at
   the bottom of the .py file (and if it's not there it probably should
   be).

2. Used a versionadded RST directive to note that this state is not yet
   available, as our automated docs builds will otherwise make it seem
   like this state is available for immediate use once your pull request
   is merged upstream.