Hello, thank you for cabal-gild, it's working great!

Though I had a little usability issue when using it to format multiple cabal files.
I thought cabal-gild would work like fourmolu where you can give it multiple files at once.
However, it seems like it silently ignores duplicated arguments and it only process the last one.

For example, this invocation:

$ cabal-gild --io ./lib/lib.cabal --io ./server/server.cabal --io ./client/client.cabal

… only format the client.cabal file. The other ones are not touched.

Would it makes sense to support this use case, or at least throw an error in that case?