bring back OsPath changes

I hope that the windows test suite failure on appveyor was fixed by
updating to a newer windows there. I have not been able to reproduce
that failure in a windows 11 VM run locally.

Config/Files/AutoStart.hs

@@ -31,7 +31,9 @@ modifyAutoStartFile func = do
 		f <- autoStartFile
 		createDirectoryIfMissing True $
 			fromRawFilePath (parentDir (toRawFilePath f))
-		viaTmp writeFile f $ unlines dirs'
+		viaTmp (writeFile . fromRawFilePath . fromOsPath)
+			(toOsPath (toRawFilePath f))
+			(unlines dirs')
 
 {- Adds a directory to the autostart file. If the directory is already
  - present, it's moved to the top, so it will be used as the default