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.

Annex/ReplaceFile.hs

@@ -33,7 +33,7 @@ replaceFileOr file action rollback = do
 	tmpfile <- liftIO $ setup tmpdir
 	go tmpfile `catchNonAsync` (const $ rollback tmpfile)
   where
-  	setup tmpdir = do
+	setup tmpdir = do
 		(tmpfile, h) <- openTempFileWithDefaultPermissions tmpdir "tmp"
 		hClose h
 		return tmpfile