docs: add plugin setup guide

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

@@ -0,0 +1,16 @@
+#pragma once
+
+namespace RE
+{
+	class BSNavmeshTriangle
+	{
+	public:
+		// members
+		std::uint16_t vertices[3];     // 00
+		std::uint16_t triangles[3];    // 06
+		float         height;          // 0C
+		std::uint32_t triangleFlags;   // 10
+		std::int8_t   traversalFlags;  // 14
+	};
+	static_assert(sizeof(BSNavmeshTriangle) == 0x18);
+}