flake.lock: Update

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:neovim/neovim/a7550a20e0c3084eacd2b4ede1e6a94f282c2fb8?dir=contrib' (2024-01-10)
  → 'github:neovim/neovim/1813661a6197c76ea6621284570aca1d56597099?dir=contrib' (2024-01-11)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/24fe8bb4f552ad3926274d29e083b79d84707da6' (2024-01-07)
  → 'github:nixos/nixpkgs/eabe8d3eface69f5bb16c18f8662a702f50c20d5' (2024-01-09)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/ea96f0c05924341c551a797aaba8126334c505d2' (2024-01-08)
  → 'github:cachix/pre-commit-hooks.nix/b0265634df1dc584585c159b775120e637afdb41' (2024-01-10)