update i3status-rust default to new format

[happysalada]

Description

The i3status-rust format has changed. The default in home-manager is not valid format anymore. Without defining a bar, it generates a cryptic error about format and {Mup} .
This PR just updates to the latest format.

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]

Hi,

Thanks for the PR.

You'll need to rebase your changes for the pipeline to succeed.

I'm surprised this is coming up since a PR fixed this issue nearly a year ago (but the PR did not update every format_mem and format_swap configuration in the file!).

[happysalada]

alright, thanks for the heads up, I just rebased.