Properly use WorldGenRegion structure manager for swamp hut cat gener…

…ation

Fixes a crash when attempting to retrieve the chunk data,
as Folia does not support off-region sync chunk loads.

Fixes #221

patches/server/0003-Threaded-Regions.patch

@@ -18028,15 +18028,15 @@ index 0dfb8109fd8c022b079da00f6a0e3fc85b57bf7a..cdc431ab27b1837b852c8fb559d0324b
          }
 
 diff --git a/src/main/java/net/minecraft/world/entity/animal/Cat.java b/src/main/java/net/minecraft/world/entity/animal/Cat.java
-index 07559b9629d4ecb40b511256f400a781e39820e0..6d24e4efeda9265a1b02c807dbed96b7db765424 100644
+index 07559b9629d4ecb40b511256f400a781e39820e0..1cd5f0178c016736ebaf0f4449262da680cc2fab 100644
 --- a/src/main/java/net/minecraft/world/entity/animal/Cat.java
 +++ b/src/main/java/net/minecraft/world/entity/animal/Cat.java
 @@ -367,7 +367,7 @@ public class Cat extends TamableAnimal implements VariantHolder<Holder<CatVarian
          BuiltInRegistries.CAT_VARIANT.getRandomElementOf(tagkey, world.getRandom()).ifPresent(this::setVariant);
          ServerLevel worldserver = world.getLevel();
 
 -        if (worldserver.structureManager().getStructureWithPieceAt(this.blockPosition(), StructureTags.CATS_SPAWN_AS_BLACK, world).isValid()) { // Paper - Fix swamp hut cat generation deadlock
-+        if (worldserver.structureManager().getStructureWithPieceAt(this.blockPosition(), StructureTags.CATS_SPAWN_AS_BLACK).isValid()) { // Paper - Fix swamp hut cat generation deadlock // Folia - region threading - properly fix this
++        if (world.structureManager().getStructureWithPieceAt(this.blockPosition(), StructureTags.CATS_SPAWN_AS_BLACK).isValid()) { // Paper - Fix swamp hut cat generation deadlock // Folia - region threading - properly fix this
              this.setVariant((Holder) BuiltInRegistries.CAT_VARIANT.getHolderOrThrow(CatVariant.ALL_BLACK));
              this.setPersistenceRequired();
          }