fix(xan): Remove unused imports

GHC 8.8 is better at detecting unused imports, it seems - all of these
are new warnings that fail under -Werror

Change-Id: I1357094d715483612deb0db4a75b3e4f8f27d2e3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/889
Reviewed-by: glittershark <grfn@gws.fyi>
Reviewed-by: BuildkiteCI
Tested-by: BuildkiteCI

users/glittershark/xanthous/src/Xanthous/Game/Draw.hs

@@ -18,17 +18,9 @@ import           Xanthous.Game.State
 import           Xanthous.Entities.Character
 import           Xanthous.Entities.Item (Item)
 import           Xanthous.Game
-                 ( GameState(..)
-                 , entities
-                 , revealedPositions
-                 , characterPosition
+                 ( characterPosition
                  , characterVisiblePositions
                  , character
-                 , MessageHistory(..)
-                 , messageHistory
-                 , GamePromptState(..)
-                 , promptState
-                 , debugState, allRevealed
                  )
 import           Xanthous.Game.Prompt
 import           Xanthous.Orphans ()