Replace 'villager' invalid entity type lang with 'mob' since that's what OpBrainsweep uses now

Author: Robotgiggle

Common/src/main/resources/assets/hexcasting/lang/en_us.flatten.json5

@@ -1037,9 +1037,9 @@
 
           entity: {
             "": "an entity",
+            mob: "a mob",
             item: "an item entity",
             player: "a player",
-            villager: "a villager",
             living: "a living entity",
           },