flake.nix: replace fenix with rust-overlay

flake.lock

@@ -1,26 +1,5 @@
 {
   "nodes": {
-    "fenix": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "rust-analyzer-src": "rust-analyzer-src"
-      },
-      "locked": {
-        "lastModified": 1713421495,
-        "narHash": "sha256-5vVF9W1tJT+WdfpWAEG76KywktKDAW/71mVmNHEHjac=",
-        "owner": "nix-community",
-        "repo": "fenix",
-        "rev": "fd47b1f9404fae02a4f38bd9f4b12bad7833c96b",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "fenix",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1713297878,
@@ -39,24 +18,27 @@
     },
     "root": {
       "inputs": {
-        "fenix": "fenix",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
       }
     },
-    "rust-analyzer-src": {
-      "flake": false,
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1713373173,
-        "narHash": "sha256-octd9BFY9G/Gbr4KfwK4itZp4Lx+qvJeRRcYnN+dEH8=",
-        "owner": "rust-lang",
-        "repo": "rust-analyzer",
-        "rev": "46702ffc1a02a2ac153f1d1ce619ec917af8f3a6",
+        "lastModified": 1720577957,
+        "narHash": "sha256-RZuzLdB/8FaXaSzEoWLg3au/mtbuH7MGn2LmXUKT62g=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "a434177dfcc53bf8f1f348a3c39bfb336d760286",
         "type": "github"
       },
       "original": {
-        "owner": "rust-lang",
-        "ref": "nightly",
-        "repo": "rust-analyzer",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
         "type": "github"
       }
     }