docs: add plugin setup guide

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

@@ -0,0 +1,18 @@
+#pragma once
+
+#include "RE/H/hkArray.h"
+
+namespace RE
+{
+	template <class T>
+	class hknpSparseCompactMap
+	{
+	public:
+	private:
+		std::uint32_t m_secondaryKeyMask;       // 0x00
+		std::uint32_t m_sencondaryKeyBits;      // 0x04
+		hkArray<T>    m_primaryKeyToIndex;      // 0x08
+		hkArray<T>    m_valueAndSecondaryKeys;  // 0x18
+	};
+	static_assert(sizeof(hknpSparseCompactMap<std::uint16_t>) == 0x28);
+}