Add back accidentally deleted doctests file (#2821)

* Add back accidentally deleted doctest file

* Update string-set-get-example.js

Author: dwdougherty

doctests/string-set-get-example.js

@@ -0,0 +1,27 @@
+// EXAMPLE: set_and_get
+// REMOVE_START
+import assert from "node:assert";
+// REMOVE_END
+
+// HIDE_START
+import { createClient } from 'redis';
+
+const client = createClient();
+
+client.on('error', err => console.log('Redis Client Error', err));
+
+await client.connect().catch(console.error);
+
+// HIDE_END
+await client.set('bike:1', 'Process 134');
+const value = await client.get('bike:1');
+console.log(value);
+// returns 'Process 134'
+//REMOVE_START
+assert.equal(value, 'Process 134');
+await client.del('bike:1');
+//REMOVE_END
+
+// HIDE_START
+await client.quit();
+// HIDE_END