feat(gs/xanthous): Allow generating creatures with items

Add an `equippedItems` field to the CreatureType raw, which provides a
chance for generating that creature with an item equipped, which goes
into a new `inventory` field on the creature entity itself. Currently
the creature doesn't actually *use* this equipped item, but it's a step.

This commit also adds a broken-dagger equipped 90% of the time to the
"husk" creature.

Change-Id: I6416c0678ba7bc1b002c5ce6119f7dc97dd86437

users/grfn/xanthous/test/Xanthous/Entities/RawsSpec.hs

@@ -4,6 +4,8 @@ module Xanthous.Entities.RawsSpec (main, test) where
 
 import Test.Prelude
 import Xanthous.Entities.Raws
+import Xanthous.Entities.RawTypes
+       (_Creature, entityName, generateParams, HasEquippedItem (equippedItem))
 
 main :: IO ()
 main = defaultMain test
@@ -12,5 +14,17 @@ test :: TestTree
 test = testGroup "Xanthous.Entities.Raws"
   [ testGroup "raws"
     [ testCase "are all valid" $ raws `deepseq` pure ()
+    , testCase "all CreatureEquippedItems reference existent entity names" $
+      let notFound
+            = raws
+              ^.. folded
+              . _Creature
+              . generateParams
+              . _Just
+              . equippedItem
+              . _Just
+              . entityName
+              . filtered (isNothing . raw)
+      in null notFound @? ("Some entities weren't found: " <> show notFound)
     ]
   ]