refactor: refactor doc layout

doc/src/windows/win_fct_helper.dox

@@ -0,0 +1,23 @@
+namespace YYCC::WinFctHelper {
+/**
+
+\page win_fct_helper Windows Function Helper
+
+This helper give a more convenient way to call Windows functions.
+
+This namespace is Windows specific.
+It will be entirely invisible in other platforms.
+
+Currently this namespace has following functions:
+
+\li #GetCurrentModule: Get the handle to current module.
+\li #GetTempDirectory: Get temporary directory in Windows.
+\li #GetModuleFileName: Get the path to module in file system by given handle.
+\li #GetLocalAppData: Get the path inside \%LOCALAPPDATA\%
+\li #IsValidCodePage: Check whether given code page number is valid.
+\li #CopyFile: The UTF8 version of Win32 \c CopyFile.
+\li #MoveFile: The UTF8 version of Win32 \c MoveFile.
+\li #DeleteFile: The UTF8 version of Win32 \c DeleteFile.
+
+*/
+}