flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/6ed03ef4c8ec36d193c18e06b9ecddde78fb7e42?narHash=sha256-tl/0cnsqB/Yt7DbaGMel2RLa7QG5elA8lkaOXli6VdY%3D' (2025-08-19)
  → 'github:nix-community/fenix/0956bc5d1df2ea800010172c6bc4470d9a22cb81?narHash=sha256-hmiTEoVAqLnn80UkreCNunnRKPucKvcg5T4/CELEtbw%3D' (2025-10-01)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/a905e3b21b144d77e1b304e49f3264f6f8d4db75?narHash=sha256-VX0B9hwhJypCGqncVVLC%2BSmeMVd/GAYbJZ0MiiUn2Pk%3D' (2025-08-18)
  → 'github:rust-lang/rust-analyzer/a6bc4a4bbe6a65b71cbf76a0cf528c47a8d9f97f?narHash=sha256-H4Hx/EuMJ9qi1WzPV4UG2bbZiDCdREtrtDvYcHr0kmk%3D' (2025-09-30)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/a58390ab6f1aa810eb8e0f0fc74230e7cc06de03?narHash=sha256-BA9MuPjBDx/WnpTJ0EGhStyfE7hug8g85Y3Ju9oTsM4%3D' (2025-08-19)
  → 'github:NixOS/nixpkgs/5b5be50345d4113d04ba58c444348849f5585b4a?narHash=sha256-FIBE1qXv9TKvSNwst6FumyHwCRH3BlWDpfsnqRDCll0%3D' (2025-10-01)

Author: sunng87