misc update

home: some keybind changes
nvim: random lsp related changes
hosts/satori: add a separate nix.nix file
home/services: random mpd update

hosts/satori/nix.nix

@@ -0,0 +1,21 @@
+{ config, pkgs, ... }:
+{
+  nix = {
+    package = pkgs.nixUnstable;
+    extraOptions = ''
+      experimental-features = nix-command flakes
+    '';
+    settings = {
+      trusted-users = [ "root" "natto" ];
+      substituters = [
+        "https://nix-gaming.cachix.org"
+        "https://nix-community.cachix.org"
+        "https://mirrors.tuna.tsinghua.edu.cn/nix-channels/store"
+      ];
+      trusted-public-keys = [
+        "nix-gaming.cachix.org-1:nbjlureqMbRAxR1gJ/f3hxemL9svXaZF/Ees8vCUUs4="
+        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+      ];
+    };
+  };
+}