docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/O/OBJ_ARMA.h

@@ -0,0 +1,16 @@
+#pragma once
+
+namespace RE
+{
+	class OBJ_ARMA
+	{
+	public:
+		// members
+		std::int8_t priorities[2];  // 0
+		std::int8_t modelRange[2];  // 2
+		std::int8_t unused[2];      // 4
+		std::int8_t soundValue;     // 6
+		float       weaponAdjust;   // 8
+	};
+	static_assert(sizeof(OBJ_ARMA) == 0xC);
+}