Remove fs::file::set_delete

Since it's Windows-only functionality with limited use.

Utilities/File.cpp

@@ -1328,15 +1328,6 @@ fs::native_handle fs::file::get_handle() const
 #endif
 }
 
-#ifdef _WIN32
-bool fs::file::set_delete(bool autodelete) const
-{
-	FILE_DISPOSITION_INFO disp;
-	disp.DeleteFileW = autodelete;
-	return SetFileInformationByHandle(get_handle(), FileDispositionInfo, &disp, sizeof(disp)) != 0;
-}
-#endif
-
 void fs::dir::xnull() const
 {
 	fmt::throw_exception<std::logic_error>("fs::dir is null");