flake: add overlay

flake.nix

@@ -12,7 +12,21 @@
     supportedSystems = ["x86_64-linux" "aarch64-linux"];
     forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
     nixpkgsFor = forAllSystems (system: import nixpkgs {inherit system;});
-    pkgs = nixpkgs.legacyPackages.x86_64-linux.pkgs;
+    additionalDeps = pkgs: [
+      pkgs.alejandra
+      pkgs.ccls
+      pkgs.gopls
+      pkgs.luaformatter
+      pkgs.nixd
+      pkgs.pyright
+      pkgs.rust-analyzer
+      pkgs.sumneko-lua-language-server
+      pkgs.svls
+      pkgs.texlab
+      pkgs.tree-sitter
+      pkgs.verible
+      pkgs.zls
+    ];
   in {
     packages = forAllSystems (system: let
       pkgs = nixpkgsFor.${system};
@@ -22,6 +36,7 @@
 
     devShells = forAllSystems (system: let
       pkgs = nixpkgsFor.${system};
+      vim = self.packages.${system};
     in {
       default = pkgs.mkShell {
         nativeBuildInputs = [
@@ -38,11 +53,23 @@
           pkgs.tree-sitter
           pkgs.verible
           pkgs.zls
-          (import ./nvim-lsp.nix {inherit pkgs;})
+          vim
         ];
       };
     });
 
+    overlays = forAllSystems (system: let
+      vim = self.packages.${system};
+      pkgs = nixpkgsFor.${system};
+    in {
+      overlay = final: prev: {
+        inherit
+          (vim)
+          additionalDeps
+          ;
+      };
+    });
+
     defaultPackage = forAllSystems (system: self.packages.${system}.nvim);
   };
 }