Follows-up 648667ac9f, which didn't move this module because
it had a local patch for exposing via module.exports and mw.lib
(instead of its default 'pluralRuleParser' global).
Restore the file back to a clean copy from upstream, and perform
the export via a separately concatenated file instead, using the
same pattern we already use for 'oojs' and 'moment'.
Change-Id: I27ee80dc34e0ad5206cf9c1ce68be3ec8811ecf8
715b6907ce