docs: add plugin setup guide

plugin/lib/commonlibf4/include/RE/S/SayOnceTopicInfos.h

@@ -0,0 +1,16 @@
+#pragma once
+
+namespace RE
+{
+	class TESTopicInfo;
+
+	class SayOnceTopicInfos
+	{
+	public:
+		// members
+		TESTopicInfo* info;       // 00
+		std::int32_t  dateStamp;  // 08
+		float         hourStamp;  // 0C
+	};
+	static_assert(sizeof(SayOnceTopicInfos) == 0x10);
+}