docs: add plugin setup guide

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

@@ -0,0 +1,40 @@
+#pragma once
+
+namespace RE
+{
+	template <class T>
+	class hkRelArray
+	{
+	public:
+		hkRelArray(){};
+
+		T& operator[](const std::int32_t a_index)
+		{
+			assert(a_index >= 0);
+			assert(a_index < m_size);
+			return reinterpret_cast<T*>(reinterpret_cast<char*>(this) + m_offset)[a_index];
+		}
+
+		const T& operator[](const std::int32_t a_index) const
+		{
+			assert(a_index >= 0);
+			assert(a_index < m_size);
+			return reinterpret_cast<const T*>(reinterpret_cast<const char*>(this) + m_offset)[a_index];
+		}
+
+		T* begin()
+		{
+			return reinterpret_cast<T*>(reinterpret_cast<char*>(this) + m_offset);
+		}
+
+		const T* begin() const
+		{
+			return reinterpret_cast<const T*>(reinterpret_cast<const char*>(this) + m_offset);
+		}
+
+	protected:
+		std::uint16_t m_size;    // 0x00
+		std::uint16_t m_offset;  // 0x02
+	};
+	static_assert(sizeof(hkRelArray<std::byte>) == 0x4);
+}