Add personal info structure update changes

One field added to indicate the GO species or whatever; the 891/892
meltan values match here. Might not be only for GO species translation,
might be for fetching models idk

PKHeX.Core/PersonalInfo/PersonalInfoGG.cs

@@ -0,0 +1,13 @@
+using System;
+
+namespace PKHeX.Core
+{
+    /// <summary>
+    /// <see cref="PersonalInfo"/> class with values from the LGPE games.
+    /// </summary>
+    public class PersonalInfoGG : PersonalInfoSM
+    {
+        public PersonalInfoGG(byte[] data) : base(data) { }
+        public int GoSpecies { get => BitConverter.ToUInt16(Data, 0x48); set => BitConverter.GetBytes((ushort)value).CopyTo(Data, 0x48); }
+    }
+}