flake.lock: Update

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:neovim/neovim/248305cf377de6710daa89a92eb8605fa5dcbb1f?dir=contrib' (2023-09-30)
  → 'github:neovim/neovim/09a17f91d0d362c6e58bfdbe3ccdeacffb0b44b9?dir=contrib' (2023-10-02)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/bd9b686c0168041aea600222be0805a0de6e6ab8' (2023-09-29)
  → 'github:nixos/nixpkgs/0396d3b0fb7f62ddc79a506ad3e6124f01d2ed0a' (2023-10-01)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/cb770e93516a1609652fa8e945a0f310e98f10c0' (2023-09-24)
  → 'github:cachix/pre-commit-hooks.nix/033453f85064ccac434dfd957f95d8457901ecd6' (2023-10-01)