Describe what you see when you walk over items

Every step the character takes, describe the entities at that position
excluding the character.

src/Xanthous/Entities/Character.hs

@@ -41,6 +41,7 @@ instance Draw Character where
 
 instance Entity Character where
   blocksVision _ = False
+  description _ = "yourself"
 
 instance Arbitrary Character where
   arbitrary = genericArbitrary