fix some mixed space+tab indentation

This fixes all instances of " \t" in the code base. Most common case
seems to be after a "where" line; probably vim copied the two space layout
of that line.

Done as a background task while listening to episode 2 of the Type Theory
podcast.

Assistant/NetMessager.hs

@@ -80,7 +80,7 @@ checkImportantNetMessages (storedclient, sentclient) = go <<~ netMessager
 queuePushInitiation :: NetMessage -> Assistant ()
 queuePushInitiation msg@(Pushing clientid stage) = do
 	tv <- getPushInitiationQueue side
-  	liftIO $ atomically $ do
+	liftIO $ atomically $ do
 		r <- tryTakeTMVar tv
 		case r of
 			Nothing -> putTMVar tv [msg]
@@ -88,7 +88,7 @@ queuePushInitiation msg@(Pushing clientid stage) = do
 				let !l' = msg : filter differentclient l
 				putTMVar tv l'
   where
-  	side = pushDestinationSide stage
+	side = pushDestinationSide stage
 	differentclient (Pushing cid _) = cid /= clientid
 	differentclient _ = True
 queuePushInitiation _ = noop