fix Windows bracketOnError warning

Author: harendra-kumar

core/src/Streamly/Internal/FileSystem/Windows/File.hsc

@@ -18,7 +18,7 @@ module Streamly.Internal.FileSystem.Windows.File
 -------------------------------------------------------------------------------
 
 import Control.Concurrent (threadDelay)
-import Control.Exception (bracketOnError, onException)
+import Control.Exception (onException)
 import Control.Monad (when, void)
 import Streamly.Internal.FileSystem.WindowsPath (WindowsPath)
 import System.IO (IOMode(..), Handle)