Fix broken unregistration of 64bit type libraries

The UnRegisterTypeLib function does currently assume 32bit type libraries (SYS_WIN32) if called without explicit `syskind` argument. This is currently the case when UnRegisterTypeLib is called implicitly from comtypes.server.register.UseCommandLine, since the `_reg_typelib_` field only contains the first 3 libID , wVerMajor and wVerMinor arguments.

Propose to fix the problem by updating the hardcoding to 64bit Windows with SYS_WIN64.

Author: forderud

comtypes/typeinfo.py

@@ -632,7 +632,7 @@ def LoadTypeLib(szFile: str) -> ITypeLib:
 
 
 def UnRegisterTypeLib(
-    libID: str, wVerMajor: int, wVerMinor: int, lcid: int = 0, syskind: int = SYS_WIN32
+    libID: str, wVerMajor: int, wVerMinor: int, lcid: int = 0, syskind: int = SYS_WIN64
 ) -> int:
     """Unregister a registered type library"""
     return _oleaut32.UnRegisterTypeLib(