ENH generalize backlight common plugin

lib/Xmobar/Plugins/BacklightCommon.hs

@@ -7,20 +7,21 @@
 module Xmobar.Plugins.BacklightCommon (startBacklight) where
 
 import Data.Internal.DBus
+import RIO
 import qualified RIO.Text as T
 import Xmobar.Plugins.Common
 
 startBacklight
-  :: RealFrac a
-  => ((Maybe a -> IO ()) -> SesClient -> IO ())
-  -> (SesClient -> IO (Maybe a))
+  :: (MonadUnliftIO m, RealFrac a)
+  => ((Maybe a -> m ()) -> SesClient -> m ())
+  -> (SesClient -> m (Maybe a))
   -> T.Text
   -> Callback
-  -> IO ()
+  -> m ()
 startBacklight matchSignal callGetBrightness icon cb = do
   withDBusClientConnection cb $ \c -> do
-    matchSignal display c
-    display =<< callGetBrightness c
+    matchSignal dpy c
+    dpy =<< callGetBrightness c
   where
     formatBrightness b = return $ T.concat [icon, T.pack $ show (round b :: Integer), "%"]
-    display = displayMaybe cb formatBrightness
+    dpy = displayMaybe cb formatBrightness