docs/flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
'github:NixOS/nixpkgs/3016b4b15d13f3089db8a41ef937b13a9e33a8df' (2025-06-30)
→ 'github:NixOS/nixpkgs/5c724ed1388e53cc231ed98330a60eb2f7be4be3' (2025-07-04)
• Updated input 'tgirlpkgs':
'path:../.?lastModified=0&narHash=sha256-TtmLp5adGliNNXiowg4a9mi35DH/F/zKggQ62u%2BnZBo%3D' (1970-01-01)
→ 'path:../.?lastModified=0&narHash=sha256-7VSMJSaadkm6ifZa/a6NrUM8kj4CC08Aif%2B5rLeZy6s%3D' (1970-01-01)

docs/flake.lock

···
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1751271578,
-        "narHash": "sha256-P/SQmKDu06x8yv7i0s8bvnnuJYkxVGBWLWHaU+tt4YY=",
+        "lastModified": 1751637120,
+        "narHash": "sha256-xVNy/XopSfIG9c46nRmPaKfH1Gn/56vQ8++xWA8itO4=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "3016b4b15d13f3089db8a41ef937b13a9e33a8df",
+        "rev": "5c724ed1388e53cc231ed98330a60eb2f7be4be3",
         "type": "github"
       },
       "original": {
···
       },
       "locked": {
         "lastModified": 0,
-        "narHash": "sha256-TtmLp5adGliNNXiowg4a9mi35DH/F/zKggQ62u+nZBo=",
+        "narHash": "sha256-7VSMJSaadkm6ifZa/a6NrUM8kj4CC08Aif+5rLeZy6s=",
         "path": "../.",
         "type": "path"
       },