add startAction parameter for KeySha

I have a use planned for this in Command.Migrate.

Sponsored-by: unqueued on Patreon

Command/Find.hs

@@ -63,7 +63,7 @@ seek o = do
 		checkNotBareRepo
 	isterminal <- liftIO $ checkIsTerminal stdout
 	seeker <- contentPresentUnlessLimited $ AnnexedFileSeeker
-		{ startAction = start o isterminal
+		{ startAction = const (start o isterminal)
 		, checkContentPresent = Nothing
 		, usesLocationLog = False
 		}