ghostty: fix configuration for bat syntax

[HeitorAugustoLN]

Description

Turns out that */ghostty/config doesn't work. So updated it to use xdg.configHome instead.

Checklist

• Change is backwards compatible.

• Code formatted with ./format.

• Code tested through nix-shell --pure tests -A run.all or nix develop --ignore-environment .#all using Flakes.

• Test cases updated/added. See example.

• Commit messages are formatted like

  {component}: {description}
  
  {long description}
  

  See CONTRIBUTING for more information and recent commit messages for examples.

• If this PR adds a new module

  • Added myself as module maintainer. See example.

Maintainer CC

[rycee]

Thanks! Merged to master now 🙂