add new struct definitions

Il2CppInspector.Common/Next/Metadata/Il2CppGenericContainer.cs

@@ -0,0 +1,13 @@
+namespace Il2CppInspector.Next.Metadata;
+
+using VersionedSerialization.Attributes;
+using GenericParameterIndex = int;
+
+[VersionedStruct]
+public partial struct Il2CppGenericContainer
+{
+    public int OwnerIndex { get; private set; }
+    public int TypeArgc { get; private set; }
+    public int IsMethod { get; private set; }
+    public GenericParameterIndex GenericParameterStart { get; private set; }
+}