Add inputs.nixpkgs.follows to rust-overlay in flake.nix

[oati]

Before this PR, the helix flake created two separate entries of nixpkgs in flake.lock.

This PR fixes this issue.

[the-mikedavis]

It looks like this updates flake.lock...

diff --git a/flake.lock b/flake.lock
index 94e443e3..5286fb50 100644
--- a/flake.lock
+++ b/flake.lock
@@ -70,22 +70,6 @@
         "type": "github"
       }
     },
-    "nixpkgs_2": {
-      "locked": {
-        "lastModified": 1637453606,
-        "narHash": "sha256-Gy6cwUswft9xqsjWxFYEnx/63/qzaFUwatcbV5GF/GQ=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "8afc4e543663ca0a6a4f496262cd05233737e732",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "ref": "nixpkgs-unstable",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "nixCargoIntegration": "nixCargoIntegration",
@@ -96,7 +80,9 @@
     "rust-overlay": {
       "inputs": {
         "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs_2"
+        "nixpkgs": [
+          "nixpkgs"
+        ]
       },
       "locked": {
         "lastModified": 1642128126,

Would you mind pushing that change as well? Otherwise lgtm 👍

[oati]

Updated!

[archseer]

Thanks!