use @nullable to fix warnings

Author: GliczDev

slime-loader/src/main/java/net/roxymc/slime/loader/Deserializers.java

@@ -8,6 +8,7 @@
 import net.roxymc.slime.world.chunk.Chunk;
 import net.roxymc.slime.world.chunk.Section;
 import net.roxymc.slime.world.entity.Entity;
+import org.jspecify.annotations.Nullable;
 
 import static net.roxymc.slime.util.ObjectUtils.nonNull;
 
@@ -64,16 +65,15 @@ public World.Deserializer world() {
         return world;
     }
 
-    @SuppressWarnings("NotNullFieldNotInitialized") // it's a builder
     public static final class Builder {
-        private Biomes.Deserializer biomes;
-        private BlockEntity.Deserializer blockEntity;
-        private BlockStates.Deserializer blockStates;
-        private Chunk.Deserializer chunk;
-        private Section.Deserializer section;
-        private Entity.Deserializer entity;
-        private Heightmaps.Deserializer heightmaps;
-        private World.Deserializer world;
+        private Biomes.@Nullable Deserializer biomes;
+        private BlockEntity.@Nullable Deserializer blockEntity;
+        private BlockStates.@Nullable Deserializer blockStates;
+        private Chunk.@Nullable Deserializer chunk;
+        private Section.@Nullable Deserializer section;
+        private Entity.@Nullable Deserializer entity;
+        private Heightmaps.@Nullable Deserializer heightmaps;
+        private World.@Nullable Deserializer world;
 
         Builder() {
         }

slime-loader/src/main/java/net/roxymc/slime/loader/SlimeLoader.java

@@ -6,6 +6,7 @@
 import com.google.common.io.ByteStreams;
 import net.roxymc.slime.serializer.SlimeSerializer;
 import net.roxymc.slime.world.World;
+import org.jspecify.annotations.Nullable;
 
 import java.io.IOException;
 import java.util.Arrays;
@@ -61,9 +62,8 @@ public byte[] save(World world) throws IOException {
         return out.toByteArray();
     }
 
-    @SuppressWarnings("NotNullFieldNotInitialized") // it's a builder
     public static class Builder {
-        private Deserializers deserializers;
+        private @Nullable Deserializers deserializers;
 
         public Builder deserializers(UnaryOperator<Deserializers.Builder> builder) {
             this.deserializers = builder.apply(new Deserializers.Builder()).build();