Fix storage not saving properly

src/main/kotlin/moe/nea/firmament/features/inventory/storageoverlay/StorageData.kt

@@ -1,7 +1,10 @@
+@file:UseSerializers(SortedMapSerializer::class)
 package moe.nea.firmament.features.inventory.storageoverlay
 
 import java.util.SortedMap
 import kotlinx.serialization.Serializable
+import kotlinx.serialization.UseSerializers
+import moe.nea.firmament.util.SortedMapSerializer
 
 @Serializable
 data class StorageData(

src/main/kotlin/moe/nea/firmament/util/SortedMapSerializer.kt

@@ -0,0 +1,23 @@
+package moe.nea.firmament.util
+
+import java.util.SortedMap
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.builtins.MapSerializer
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+
+class SortedMapSerializer<K : Comparable<K>, V>(val keyDelegate: KSerializer<K>, val valueDelegate: KSerializer<V>) :
+    KSerializer<SortedMap<K, V>> {
+    val mapSerializer = MapSerializer(keyDelegate, valueDelegate)
+    override val descriptor: SerialDescriptor
+        get() = mapSerializer.descriptor
+
+    override fun deserialize(decoder: Decoder): SortedMap<K, V> {
+        return (mapSerializer.deserialize(decoder).toSortedMap(Comparator.naturalOrder()))
+    }
+
+    override fun serialize(encoder: Encoder, value: SortedMap<K, V>) {
+        mapSerializer.serialize(encoder, value)
+    }
+}