get rid of implicitMessages state

Oh joyous day, this is probably git-annex's oldest implementation wart,
source of much unncessary bother.

Now that we have a StartMessage, showEndResult' can look at it to know
if it needs to display an end message or not.

This is also going to be faster, because it avoids an uncessary state
lookup for each file processed.

Messages.hs

@@ -9,6 +9,7 @@ module Messages (
 	showStart,
 	showStart',
 	showStartMessage,
+	showEndMessage,
 	StartMessage(..),
 	ActionItem(..),
 	mkActionItem,
@@ -43,7 +44,6 @@ module Messages (
 	debugEnabled,
 	commandProgressDisabled,
 	outputMessage,
-	implicitMessage,
 	withMessageState,
 	prompt,
 ) where
@@ -97,13 +97,15 @@ showStartMessage (StartUsualMessages command ai) = do
 	outputType <$> Annex.getState Annex.output >>= \case
 		QuietOutput -> Annex.setOutput NormalOutput
 		_ -> noop
-	Annex.changeState $ \s -> s
-		{ Annex.output = (Annex.output s) { implicitMessages = True } }
 	showStartMessage (StartMessage command ai)
 showStartMessage (CustomOutput _) = do
 	Annex.setOutput QuietOutput
-	Annex.changeState $ \s -> s
-		{ Annex.output = (Annex.output s) { implicitMessages = False } }
+
+-- Only show end result if the StartMessage is one that gets displayed.
+showEndMessage :: StartMessage -> Bool -> Annex ()
+showEndMessage (StartMessage _ _) = showEndResult
+showEndMessage (StartUsualMessages _ _) = showEndResult
+showEndMessage (CustomOutput _) = const noop
 
 showNote :: String -> Annex ()
 showNote s = outputMessage (JSON.note s) $ "(" ++ s ++ ") "
@@ -275,12 +277,6 @@ commandProgressDisabled = withMessageState $ \s -> return $
 		JSONOutput _ -> True
 		NormalOutput -> concurrentOutputEnabled s
 
-{- Use to show a message that is displayed implicitly, and so might be
- - disabled when running a certian command that needs more control over its
- - output. -}
-implicitMessage :: Annex () -> Annex ()
-implicitMessage = whenM (implicitMessages <$> Annex.getState Annex.output)
-
 {- Prevents any concurrent console access while running an action, so
  - that the action is the only thing using the console, and can eg prompt
  - the user.