Restore short option for logfile (haskell#3672)

I meant to leave the old options in place. The short option is only
there for the hidden old option, so it's not shown. That means what new
users see is consistent across all the options.

Author: michaelpj

src/Ide/Arguments.hs

@@ -149,6 +149,7 @@ arguments plugins = GhcideArguments
           <> help "Send logs to a file"
            )) <|> (optional (strOption
            ( long "logfile"
+          <> short 'l'
           <> metavar "LOGFILE"
           <> help "Send logs to a file"
           -- deprecated alias so users don't need to update their CLI calls