remove ocaml overlay

flake.lock

@@ -73,7 +73,7 @@
           "lix"
         ],
         "nixpkgs": [
-          "ocaml-overlay"
+          "nixpkgs"
         ]
       },
       "locked": {
@@ -138,34 +138,13 @@
         "type": "github"
       }
     },
-    "ocaml-overlay": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1734156418,
-        "narHash": "sha256-7I6hKojqDm0Z+q9ZvDk8R5J/TfoPbprmVquwfQIzQrg=",
-        "owner": "nix-ocaml",
-        "repo": "nix-overlays",
-        "rev": "3bd751c1d602713195432d4818b35d29c4b1dccc",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-ocaml",
-        "repo": "nix-overlays",
-        "type": "github"
-      }
-    },
     "root": {
       "inputs": {
         "flake-utils": "flake-utils",
         "lix": "lix",
         "lix-module": "lix-module",
         "nh": "nh",
-        "nixpkgs": "nixpkgs_2",
-        "ocaml-overlay": "ocaml-overlay"
+        "nixpkgs": "nixpkgs_2"
       }
     },
     "systems": {