showStart variant for when there's no worktree file

Clean up some uses of showStart with "" for the file,
or in some cases, a non-filename description string. That would
generate bad json, although none of the commands doing that
supported --json.

Using "" for the file resulted in output like "foo  rest";
now the extra space is eliminated.

This commit was sponsored by Fernando Jimenez on Patreon.

Command/Indirect.hs

@@ -42,7 +42,7 @@ start = ifM isDirect
 
 perform :: CommandPerform
 perform = do
-	showStart "commit" ""
+	showStart' "commit" Nothing
 	whenM stageDirect $ do
 		showOutput
 		void $ inRepo $ Git.Branch.commitCommand Git.Branch.ManualCommit
@@ -100,6 +100,6 @@ perform = do
 	
 cleanup :: CommandCleanup
 cleanup = do
-	showStart "indirect" ""
+	showStart' "indirect" Nothing
 	showEndOk
 	return True