docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/H/hkPadSpu.h

@@ -0,0 +1,18 @@
+#pragma once
+
+namespace RE
+{
+	template <class T>
+	class hkPadSpu
+	{
+	public:
+		void operator=(T val) { storage = val; }
+		T    val() const { return storage; }
+		T&   operator*() const { return &storage; }
+		T*   operator->() const { return &storage; }
+
+		// members
+		T storage;  // 00
+	};
+	static_assert(sizeof(hkPadSpu<void*>) == 0x08);
+}