Remove `terraform-fmt` wrapper

[lbodor]

Since the time terraform-fmt wrapper was added to git-hooks.nix 5 years ago, both terraform and tofu now support formatting multiple files.

https://github.com/hashicorp/terraform/pull/31286 https://github.com/hashicorp/terraform/pull/28191

[lbodor]

I just noticed https://github.com/cachix/git-hooks.nix/pull/419, which also makes the change to format individual files, rather than entire directories, like the existing terraform-fmt wrapper.

[domenkozar]

Should we rather use #419?

[lbodor]

Should we rather use #419?

Sure, that would be fine.

[sandydoo]

Merged #419, which is practically identical to this.