add nushell and carapace

modules/shell/default.nix

@@ -0,0 +1,13 @@
+{ config, impurity, ... }: {
+  home-manager.users.${config.main-user} = { config, ... }: {
+    programs.nushell = {
+      enable = true;
+      configFile.text = "source ${impurity.link ./nushell.nu}";
+    };
+
+    programs.carapace = {
+      enable = true;
+      enableNushellIntegration = true;
+    };
+  };
+}

modules/shell/nushell.nu

@@ -0,0 +1,5 @@
+$env.config.show_banner = false
+$env.config.buffer_editor = ["emacsclient", "-c"]
+$env.CARAPACE_BRIDGES = ["fish", "zsh", "bash"]
+
+alias e = emacsclient -c