Hi!
I think next messages should use plural:
'watchlistcount' => 'You have {{PLURAL:$1|item|items}} on your
watchlist, including talk pages.'
'watchlistcleardone' => 'Your watchlist has been cleared.
{{PLURAL:$1|item was removed|items were removed}}.'
'watchdetails' => '* {{PLURAL:$1|page|pages}} watched not counting talk pages
* [[Special:Watchlist/edit|Show and edit complete watchlist]]
* [[Special:Watchlist/clear|Remove all pages]]'
'watchlistcontains' => "Your watchlist contains {{PLURAL:$1|page|pages}}."
I tried to translate last one but PLURAL didn't work correctly.
With best regards,
Eugene.