Improve resuming interrupted download when using yt-dlp or youtube-dl

Fixes a failure like this:

curl: (33) HTTP server doesn't seem to support byte ranges. Cannot resume.

That happens because the whole web page has already been downloaded
previously, and kept, so now addurl tries to download it, and curl asks the
server to resume from the last byte. And youtube.com can't, for whatever
stupid reason.

So, delete the temp file after determining that youtube-dl can be used.

Command/AddUrl.hs

@@ -343,9 +343,10 @@ downloadWeb addunlockedmatcher o url urlinfo file =
 	-- Ask youtube-dl what filename it will download first, 
 	-- so it's only used when the file contains embedded media.
 	tryyoutubedl tmp backend = youtubeDlFileNameHtmlOnly url >>= \case
-		Right mediafile -> 
+		Right mediafile -> do
+			liftIO $ liftIO $ removeWhenExistsWith R.removeLink tmp
 			let f = youtubeDlDestFile o file (toRawFilePath mediafile)
-			in lookupKey f >>= \case
+			lookupKey f >>= \case
 				Just k -> alreadyannexed f k
 				Nothing -> dl f
 		Left err -> checkRaw (Just err) o (pure Nothing) (normalfinish tmp backend)