docs: add plugin setup guide

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

@@ -0,0 +1,14 @@
+#pragma once
+
+namespace RE
+{
+	class BSNavmeshInfo;
+
+	class BSNavmeshTriHandle
+	{
+	public:
+		BSNavmeshInfo* pNavMeshInfo;  // 00
+		std::uint16_t  triangle;      // 08
+	};
+	static_assert(sizeof(BSNavmeshTriHandle) == 0x10);
+}