flake.lock: Update

Flake lock file updates:

• Updated input 'fenix':
    'github:nix-community/fenix/25db7a6f4de7dea678620785e03fbc4560c00672?narHash=sha256-wC9PR%2BrPjmcpnPdOIDwyNwQiRhNsuDs3oZY3t42f4uA%3D' (2025-07-26)
  → 'github:nix-community/fenix/6ed03ef4c8ec36d193c18e06b9ecddde78fb7e42?narHash=sha256-tl/0cnsqB/Yt7DbaGMel2RLa7QG5elA8lkaOXli6VdY%3D' (2025-08-19)
• Updated input 'fenix/rust-analyzer-src':
    'github:rust-lang/rust-analyzer/51e77c9d7b9b99f7a230bf5179ef1343befd71ac?narHash=sha256-5XbVpJwiy%2Bsw1v4PXSAz4lgJnVna6xkzqyZtoHymFJA%3D' (2025-07-25)
  → 'github:rust-lang/rust-analyzer/a905e3b21b144d77e1b304e49f3264f6f8d4db75?narHash=sha256-VX0B9hwhJypCGqncVVLC%2BSmeMVd/GAYbJZ0MiiUn2Pk%3D' (2025-08-18)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/6027c30c8e9810896b92429f0092f624f7b1aace?narHash=sha256-cnL5WWn/xkZoyH/03NNUS7QgW5vI7D1i74g48qplCvg%3D' (2025-07-25)
  → 'github:NixOS/nixpkgs/f937f8ecd1c70efd7e9f90ba13dfb400cf559de4?narHash=sha256-4/Jd%2BLkQ2ssw8luQVkqVs9spDBVE6h/u/hC/tzngsPo%3D' (2025-08-22)

Author: github-actions[bot]