Add raid spawn initial docs

linq dump code I used for ez vis:
var sav = new SAV8SWSH(File.ReadAllBytes(@"D:\Kurt\Downloads\main
(7)"));
var blocks = sav.Blocks;
var raid = blocks.Raid;
raid.GetAllRaids().Dump();

PKHeX.Core/Saves/Substructures/Gen8/RaidSpawnList8.cs

@@ -1,7 +1,45 @@
-namespace PKHeX.Core
+using System;
+
+namespace PKHeX.Core
 {
     public sealed class RaidSpawnList8 : SaveBlock
     {
         public RaidSpawnList8(SaveFile sav, SCBlock block) : base(sav, block.Data) { }
+
+        private const int RaidCount = 111;
+
+        public RaidSpawnDetail GetRaid(int entry) => new RaidSpawnDetail(Data, entry * RaidSpawnDetail.SIZE);
+
+        public RaidSpawnDetail[] GetAllRaids()
+        {
+            var result = new RaidSpawnDetail[RaidCount];
+            for (int i = 0; i < result.Length; i++)
+                result[i] = GetRaid(i);
+            return result;
+        }
+    }
+
+    public class RaidSpawnDetail
+    {
+        public const int SIZE = 0x18;
+
+        private readonly byte[] Data;
+        private readonly int Offset;
+
+        public RaidSpawnDetail(byte[] data, int ofs)
+        {
+            Data = data;
+            Offset = ofs;
+        }
+
+        public ulong Hash => BitConverter.ToUInt64(Data, Offset + 0);
+        public ulong Seed => BitConverter.ToUInt64(Data, Offset + 8);
+
+        public byte V10 => Data[Offset + 0x10];
+        public byte V11 => Data[Offset + 0x11];
+        public byte V12 => Data[Offset + 0x12];
+        public byte V13 => Data[Offset + 0x13];
+
+        // The games use a xoroshiro RNG to create the PKM from the stored seed.
     }
 }