[chore] flake.lock: update inputs

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/6e99f2a27d600612004fbd2c3282d614bfee6421' (2024-08-30)
  → 'github:NixOS/nixpkgs/6f6c45b5134a8ee2e465164811e451dcb5ad86e3' (2024-09-03)
• Updated input 'nixvim':
    'github:nix-community/nixvim/d928d6deb18274b12edfc10681e52e50b51c3e35' (2024-09-04)
  → 'github:nix-community/nixvim/84249a9dabdf930d968d248024c4d6240ee14548' (2024-09-05)
• Updated input 'unstable':
    'github:NixOS/nixpkgs/12228ff1752d7b7624a54e9c1af4b222b3c1073b' (2024-08-31)
  → 'github:NixOS/nixpkgs/ad416d066ca1222956472ab7d0555a6946746a80' (2024-09-04)

flake.lock

@@ -350,11 +350,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1725001927,
+        "lastModified": 1725407940,
-        "narHash": "sha256-eV+63gK0Mp7ygCR0Oy4yIYSNcum2VQwnZamHxYTNi+M=",
+        "narHash": "sha256-tiN5Rlg/jiY0tyky+soJZoRzLKbPyIdlQ77xVgREDNM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "6e99f2a27d600612004fbd2c3282d614bfee6421",
+        "rev": "6f6c45b5134a8ee2e465164811e451dcb5ad86e3",
         "type": "github"
       },
       "original": {
@@ -383,11 +383,11 @@
         "treefmt-nix": "treefmt-nix"
       },
       "locked": {
-        "lastModified": 1725478192,
+        "lastModified": 1725563454,
-        "narHash": "sha256-cFNboKDdDCaGWugw2726jq0myzCCiotZ0M/DruWFu8c=",
+        "narHash": "sha256-RQ9aKwXmqNHMBFOlHEUVrAFo7YHJSVn4nBgi2rcaCY4=",
         "owner": "nix-community",
         "repo": "nixvim",
-        "rev": "cdb2e79e5179029a99a7e1e0d4bb450861ef7c29",
+        "rev": "84249a9dabdf930d968d248024c4d6240ee14548",
         "type": "github"
       },
       "original": {
@@ -502,11 +502,11 @@
     },
     "unstable": {
       "locked": {
-        "lastModified": 1725103162,
+        "lastModified": 1725432240,
-        "narHash": "sha256-Ym04C5+qovuQDYL/rKWSR+WESseQBbNAe5DsXNx5trY=",
+        "narHash": "sha256-+yj+xgsfZaErbfYM3T+QvEE2hU7UuE+Jf0fJCJ8uPS0=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "12228ff1752d7b7624a54e9c1af4b222b3c1073b",
+        "rev": "ad416d066ca1222956472ab7d0555a6946746a80",
         "type": "github"
       },
       "original": {