docs(examples/with-iron-session): fix mutate + fetch, add TypeScript …

…example link (#25889)

This updates the with-iron-session example with:
- updated way to mutate + fetch (re: vvo/iron-session#329)
- updated readme to include TypeScript example link

Requirements:
- [x] Make sure the linting passes

examples/with-iron-session/README.md

@@ -1,9 +1,22 @@
 # Example application using [`next-iron-session`](https://github.com/vvo/next-iron-session)
 
+---
+
+<p align="center"><b>Online demo at <a href="https://next-iron-session.vercel.app/">https://next-iron-session.vercel.app/</a> 👀</b></p>
+
+---
+
 This example creates an authentication system that uses a **signed and encrypted cookie to store session data**. It relies on [`next-iron-session`](https://github.com/vvo/next-iron-session).
 
 It uses current best practices for authentication in the Next.js ecosystem.
 
+On the next-iron-session repository (https://github.com/vvo/next-iron-session) you'll find:
+
+- full API documentation and explanations on how it works
+- [TypeScript example](https://github.com/vvo/next-iron-session/tree/master/examples/next-typescript)
+- [JavaScript example](https://github.com/vvo/next-iron-session/tree/master/examples/next.js)
+- [Express.js example](https://github.com/vvo/next-iron-session/tree/master/examples/express)
+
 **Features:**
 
 - [Static Generation](https://nextjs.org/docs/basic-features/pages#static-generation-recommended) (SG), recommended example
@@ -15,13 +28,7 @@ It uses current best practices for authentication in the Next.js ecosystem.
 [`next-iron-session`](https://github.com/vvo/next-iron-session) also supports:
 
 - Express / Connect middlewares
-- Multiple encryption keys (password) to allow for seamless updates or just password rotation
-
----
-
-<p align="center"><b>Online demo at <a href="https://next-iron-session.vercel.app/">https://next-iron-session.vercel.app/</a> 👀</b></p>
-
----
+- Multiple encryption keys (passwords) to allow for seamless updates or just password rotation
 
 ## Deploy your own
 

examples/with-iron-session/pages/login.js

@@ -20,8 +20,8 @@ const Login = () => {
     }
 
     try {
-      await mutateUser(
-        fetchJson('/api/login', {
+      mutateUser(
+        await fetchJson('/api/login', {
           method: 'POST',
           headers: { 'Content-Type': 'application/json' },
           body: JSON.stringify(body),