Update doctest client with latest v4 release (#2844)

examples/dump-and-restore.js

@@ -0,0 +1,22 @@
+// This example demonstrates the use of the DUMP and RESTORE commands
+
+import { commandOptions, createClient } from 'redis';
+
+const client = createClient();
+await client.connect();
+
+// DUMP a specific key into a local variable
+const dump = await client.dump(
+    commandOptions({ returnBuffers: true }),
+    'source'
+);
+
+// RESTORE into a new key
+await client.restore('destination', 0, dump);
+
+// RESTORE and REPLACE an existing key
+await client.restore('destination', 0, dump, {
+    REPLACE: true
+});
+
+await client.quit();