flake.lock: Update

Flake lock file updates:

• Updated input 'nightly-overlay':
    'github:nix-community/neovim-nightly-overlay/3d6e49088eae842b6c0556fba66cfb14123f0d59?narHash=sha256-QTw0q1dJnoFygq9aiwjrXsX5cZEwruVzPz3VKg8KemQ%3D' (2024-12-29)
  → 'github:nix-community/neovim-nightly-overlay/fd381a5a19f553c2466dc437fb94fcf799d77e82?narHash=sha256-ibHgAkr8OXAP8MRBo4Z7AIaVdOHywGR2J8R50vZCQjI%3D' (2024-12-30)
• Updated input 'nightly-overlay/neovim-src':
    'github:neovim/neovim/2b07b14eacf3197754c63f42f9c880e85960eef2?narHash=sha256-e1KLj%2B283Znt14U9DkKw%2BzPqShe0AkFPGpT44BhZ9KU%3D' (2024-12-28)
  → 'github:neovim/neovim/e4bc8b5967d22840c1e52c97acab0f77107cd48c?narHash=sha256-PMeWazyxGxpA6UeVrWH/ur8WuqliGxXlRjTTQdMiYVc%3D' (2024-12-29)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/7cc0bff31a3a705d3ac4fdceb030a17239412210?narHash=sha256-7QEFnKkzD13SPxs%2BUFR5bUFN2fRw%2BGlL0am72ZjNre4%3D' (2024-12-27)
  → 'github:NixOS/nixpkgs/6d97d419e5a9b36e6293887a89a078cf85f5a61b?narHash=sha256-opBsbR/nrGxiiF6XzlVluiHYb6yN/hEwv%2BlBWTy9xoM%3D' (2024-12-30)