docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/B/BGSInventoryItemEvent.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "RE/B/BSPointerHandle.h"
+
+namespace RE
+{
+	namespace InventoryInterface
+	{
+		class Handle;
+	}
+
+	namespace BGSInventoryItemEvent
+	{
+		class Event
+		{
+		public:
+			ObjectRefHandle             owner;  // 00
+			InventoryInterface::Handle* item;   // 04
+		};
+	}
+}