zed-editor: add module

Add a simple module for zed-editor, a simple editor written in Rust.

tests/modules/programs/zed-editor/keymap.nix

@@ -0,0 +1,39 @@
+# Test custom keymap functionality
+{ config, ... }:
+
+{
+  programs.zed-editor = {
+    enable = true;
+    package = config.lib.test.mkStubPackage { };
+    userKeymaps = [
+      { bindings = { up = "menu::SelectPrev"; }; }
+      {
+        context = "Editor";
+        bindings = { escape = "editor::Cancel"; };
+      }
+    ];
+  };
+
+  nmt.script = let
+    expectedContent = builtins.toFile "expected.json" ''
+      [
+        {
+          "bindings": {
+            "up": "menu::SelectPrev"
+          }
+        },
+        {
+          "bindings": {
+            "escape": "editor::Cancel"
+          },
+          "context": "Editor"
+        }
+      ]
+    '';
+
+    keymapPath = ".config/zed/keymap.json";
+  in ''
+    assertFileExists "home-files/${keymapPath}"
+    assertFileContent "home-files/${keymapPath}" "${expectedContent}"
+  '';
+}