feat(xanthous): Add a method to get the name for a type of entity

I didn't end up using this directly for the thing I was doing, but it
still seems generally useful enough that I'm keeping it around for now

Change-Id: I05c8902d75845f2230ec2373a9677d61cfaafafd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3206
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

users/grfn/xanthous/test/Xanthous/Game/StateSpec.hs

@@ -0,0 +1,25 @@
+--------------------------------------------------------------------------------
+module Xanthous.Game.StateSpec (main, test) where
+--------------------------------------------------------------------------------
+import           Test.Prelude
+--------------------------------------------------------------------------------
+import           Xanthous.Game.State
+import           Xanthous.Entities.Raws (raws, entityFromRaw)
+--------------------------------------------------------------------------------
+
+main :: IO ()
+main = defaultMain test
+
+test :: TestTree
+test = testGroup "Xanthous.Game.StateSpec"
+  [ testGroup "entityTypeName"
+    [ testCase "for a creature" $
+        let gormlakRaw = raws ^?! ix "gormlak"
+            creature = entityFromRaw gormlakRaw
+        in entityTypeName creature @?= "Creature"
+    , testCase "for an item" $
+        let stickRaw = raws ^?! ix "stick"
+            item = entityFromRaw stickRaw
+        in entityTypeName item @?= "Item"
+    ]
+  ]