nix flake show is cluttered with information I'm not interested in

[bew]

Is your feature request related to a problem? Please describe.

We had #6985 describing how nix flake show initially tried to evaluate all systems.
Now that #6988 is merged nix only evaluates the attributes for the current system (by default).

However it still clutters the output with all the systems for each top-level outputs 😠

For example nix flake show github:garnix-io/sigbovik-music will output:

github:garnix-io/sigbovik-music/ff983a1791fad30a6988f6451ac4f0726f30b2fb
├───formatter
│   ├───aarch64-darwin omitted (use '--all-systems' to show)
│   ├───aarch64-linux omitted (use '--all-systems' to show)
│   ├───x86_64-darwin omitted (use '--all-systems' to show)
│   └───x86_64-linux: package 'nixpkgs-fmt-1.3.0'
└───packages
    ├───aarch64-darwin
    │   ├───bass omitted (use '--all-systems' to show)
    │   ├───default omitted (use '--all-systems' to show)
    │   ├───melody omitted (use '--all-systems' to show)
    │   └───song omitted (use '--all-systems' to show)
    ├───aarch64-linux
    │   ├───bass omitted (use '--all-systems' to show)
    │   ├───default omitted (use '--all-systems' to show)
    │   ├───melody omitted (use '--all-systems' to show)
    │   └───song omitted (use '--all-systems' to show)
    ├───x86_64-darwin
    │   ├───bass omitted (use '--all-systems' to show)
    │   ├───default omitted (use '--all-systems' to show)
    │   ├───melody omitted (use '--all-systems' to show)
    │   └───song omitted (use '--all-systems' to show)
    └───x86_64-linux
        ├───bass: package 'sequence-of-145-notes.wav'
        ├───default: package 'garnix-music'
        ├───melody: package 'sequence-of-34-notes.wav'
        └───song: package 'overlay-of-180-notes.wav'

But I'm really only interested in my current system, all the omitted (use '--all-systems' to show) really clutters the output and makes me miss and actively search what I actually want to see! (and could directly see if this clutter wasn't there)

Describe the solution you'd like
What I'm really interested in are these lines of the output:

github:garnix-io/sigbovik-music/ff983a1791fad30a6988f6451ac4f0726f30b2fb
├───formatter
│   └───x86_64-linux: package 'nixpkgs-fmt-1.3.0'
└───packages
    └───x86_64-linux
        ├───bass: package 'sequence-of-145-notes.wav'
        ├───default: package 'garnix-music'
        ├───melody: package 'sequence-of-34-notes.wav'
        └───song: package 'overlay-of-180-notes.wav'

To avoid hiding information too much there could be a header saying something along the lines of:

Showing only outputs matching the current system (x86_64-linux).
Other systems are available: aarch64-darwin aarch64-linux x86_64-darwin
(use '--all-systems' to show all outputs)

This could also be exposed in a different way, like (only showing packages output):

github:garnix-io/sigbovik-music/ff983a1791fad30a6988f6451ac4f0726f30b2fb
└───packages
    └───x86_64-linux (+3 other systems, use `--all-systems` to show)
        ├───bass: package 'sequence-of-145-notes.wav'
        ├───default: package 'garnix-music'
        ├───melody: package 'sequence-of-34-notes.wav'
        └───song: package 'overlay-of-180-notes.wav'

Describe alternatives you've considered
Training my eyes to avoid seeing unwanted information... but I don't think it's a good idea... 👀

Priorities

Add 👍 to issues you find important.

[Atry]

Try grep!

$ nix flake show github:garnix-io/sigbovik-music | grep -v omitted

github:garnix-io/sigbovik-music/ff983a1791fad30a6988f6451ac4f0726f30b2fb
├───formatter
│   └───x86_64-linux: package 'nixpkgs-fmt-1.3.0'
└───packages
    ├───aarch64-darwin
    ├───aarch64-linux
    ├───x86_64-darwin
    └───x86_64-linux
        ├───bass: package 'sequence-of-145-notes.wav'
        ├───default: package 'garnix-music'
        ├───melody: package 'sequence-of-34-notes.wav'
        └───song: package 'overlay-of-180-notes.wav'