[chore] flake.lock: update inputs

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/32e940c7c420600ef0d1ef396dc63b04ee9cad37' (2024-10-23)
  → 'github:NixOS/nixpkgs/cd3e8833d70618c4eea8df06f95b364b016d4950' (2024-10-26)
• Updated input 'nixvim':
    'github:nix-community/nixvim/4726334e4413ff55f1db3768c8d08722abbf09cf' (2024-10-24)
  → 'github:nix-community/nixvim/a20fbbc4b9665ec215e7bea061a1d64f6fd652ce' (2024-10-27)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/aac86347fb5063960eccb19493e0cadcdb4205ca' (2024-10-22)
  → 'github:numtide/treefmt-nix/bae131e525cc8718da22fbeb8d8c7c43c4ea502a' (2024-10-27)
• Updated input 'unstable':
    'github:NixOS/nixpkgs/2768c7d042a37de65bb1b5b3268fc987e534c49d' (2024-10-23)
  → 'github:NixOS/nixpkgs/18536bf04cd71abd345f9579158841376fdd0c5a' (2024-10-25)