Use POINTER(IID) instead of POINTER(GUID)

This change nothing as IID=GUID, but it is just to make more obvious that we respect the documentation: https://learn.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-dwritecreatefactory

find_system_fonts_filename/windows/dwrite.py

@@ -1,5 +1,5 @@
 from .gdi32 import LOGFONTW
-from comtypes import GUID, HRESULT, IUnknown, STDMETHOD
+from comtypes import GUID, HRESULT, IID, IUnknown, STDMETHOD
 from ctypes import POINTER, windll, wintypes
 from enum import IntEnum, IntFlag
 
@@ -347,4 +347,4 @@ def __init__(self) -> None:
         # https://learn.microsoft.com/en-us/windows/win32/api/dwrite/nf-dwrite-dwritecreatefactory
         self.DWriteCreateFactory = dwrite.DWriteCreateFactory
         self.DWriteCreateFactory.restype = HRESULT
-        self.DWriteCreateFactory.argtypes = [wintypes.UINT, POINTER(GUID), POINTER(POINTER(IUnknown))]
+        self.DWriteCreateFactory.argtypes = [wintypes.UINT, POINTER(IID), POINTER(POINTER(IUnknown))]