zellij: fix configuration for darwin

[marsam]

Description

Zellij uses a different path to hold its configuration on Darwin.
See: https://zellij.dev/documentation/configuration.html

Checklist

• Change is backwards compatible.

• Code formatted with ./format.

• Code tested through nix-shell --pure tests -A run.all.

• 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.

  • Added myself and the module files to .github/CODEOWNERS.

[berbiche]

Thanks! LGTM

edit: I cannot merge due to the pipeline failure (upstream nixpkgs package issue).

[rycee]

Thanks! Merged to master now.