chore: don't pin rust overlay nixpkgs to normal nixpkgs

flake.lock

@@ -34,6 +34,22 @@
         "type": "github"
       }
     },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1774794121,
+        "narHash": "sha256-gih24b728CK8twDNU7VX9vVYK2tLEXvy9gm/GKq2VeE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "c397ef6af68c018462d786e1b65384abc472a907",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
@@ -43,9 +59,7 @@
     },
     "rust-overlay": {
       "inputs": {
-        "nixpkgs": [
+        "nixpkgs": "nixpkgs_2"
-          "nixpkgs"
-        ]
       },
       "locked": {
         "lastModified": 1774926780,

flake.nix

@@ -5,7 +5,6 @@
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
-      inputs.nixpkgs.follows = "nixpkgs";
     };
     flake-utils.url = "github:numtide/flake-utils";
   };