nix(home-manager): enable/configure helix editor

home.nix

@@ -4,4 +4,37 @@
   home.stateVersion = "22.11";
   programs.home-manager.enable = true;
   programs.home-manager.path = "$HOME/utils/dotfiles";
+
+  programs.helix.enable = true;
+  # https://docs.helix-editor.com/from-vim.html
+  # https://github.com/helix-editor/helix/wiki/Migrating-from-Vim
+  programs.helix.settings = {
+    theme = "dracula";
+    editor = {
+      line-number = "relative";
+      cursor-shape = {
+        insert = "bar";
+        normal = "block";
+      };
+      whitespace = {
+        render = "all";
+        # or control each character
+        #render = {
+        #  space = "all";
+        #  tab = "all";
+        #  newline = "none";
+        #};
+
+        characters = {
+          space = "·";
+          nbsp = "⍽";
+          tab = "→";
+          newline = "¬";
+          # Tabs will look like "→···" (depending on tab width)
+          tabpad = "·";
+        };
+      };
+      lsp.display-messages = true;
+    };
+  };
 }