feat(flakes): acevif/swiftformat-nix

[acevif]

Summary

Add acevif/swiftformat-nix to the manual flakes index.

This flake exposes versioned SwiftFormat packages across Linux and Darwin, which makes it useful as a flake-specific search target even though swiftformat itself also exists in nixpkgs.

Details

• repository: https://github.com/acevif/swiftformat-nix
• default branch: main
• license: MIT
• exported packages include versioned swiftformat_* attrs plus swiftformat and default

Verification

• git diff --check
• local nix run .#flake-info -- --json group ./flakes/manual.toml manual --report --with-gc could not be completed on this macOS host because nixos-search#flake-info currently fails to build here with darwin.apple_sdk_11_0 has been removed
• upstream PR CI should run the existing flake import check on Ubuntu

[raboof]

OK if CI agrees

[raboof]

failure seems to be #1171

[raboof]

could you rebase?