clean up nixvim config

nixvim/keymaps.nix

@@ -0,0 +1,29 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+{
+  programs.nixvim = {
+    keymaps = [
+      {
+        key = "<C-f>";
+        action = "<cmd> lua vim.lsp.buf.format() <cr>";
+      }
+      {
+        key = "<leader>t";
+        action = "<cmd> terminal <cr>";
+      }
+      {
+        key = "<esc>";
+        action = "<c-\\><c-n>";
+        mode = "t";
+      }
+      {
+        key = "<leader-w>";
+        action = "<cmd> lua bdelete! <cr>";
+      }
+    ];
+  };
+}