Convert catch-all-routes example to TypeScript (vercel#38188)

Converted Catch All Routes example over to TypeScript to match the Contribution guidelines.

## Documentation / Examples

- [X] Make sure the linting passes by running `pnpm lint`
- [X] The examples guidelines are followed from [our contributing doc](https://github.com/vercel/next.js/blob/canary/contributing.md#adding-examples)

Author: maxproske

examples/catch-all-routes/components/header.js renamed to examples/catch-all-routes/components/header.tsx

@@ -4,29 +4,25 @@ const Header = () => (
   <header>
     <ul>
       <li>
-        <Link href="/">
-          <a>Home</a>
-        </Link>
+        <Link href="/">Home</Link>
       </li>
       <li>
-        <Link href="/about">
-          <a>About</a>
-        </Link>
+        <Link href="/about">About</Link>
       </li>
       <li>
         <Link
           href="/post/[...slug]"
           as="/post/2020/first-post/with/catch/all/routes"
         >
-          <a>First Post</a>
+          First Post
         </Link>
       </li>
       <li>
         <Link
           href="/post/[...slug]"
           as="/post/2020/second-post/with/catch/all/routes"
         >
-          <a>Second Post</a>
+          Second Post
         </Link>
       </li>
     </ul>

examples/catch-all-routes/next-env.d.ts

@@ -0,0 +1,5 @@
+/// <reference types="next" />
+/// <reference types="next/image-types/global" />
+
+// NOTE: This file should not be edited
+// see https://nextjs.org/docs/basic-features/typescript for more information.

examples/catch-all-routes/package.json

@@ -7,7 +7,13 @@
   },
   "dependencies": {
     "next": "latest",
-    "react": "^17.0.2",
-    "react-dom": "^17.0.2"
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0"
+  },
+  "devDependencies": {
+    "@types/node": "^18.0.0",
+    "@types/react": "^18.0.14",
+    "@types/react-dom": "^18.0.5",
+    "typescript": "^4.7.4"
   }
 }

examples/catch-all-routes/pages/about.js renamed to examples/catch-all-routes/pages/about.tsx

@@ -3,7 +3,7 @@ import Header from '../../components/header'
 
 const Comment = () => {
   const router = useRouter()
-  const slug = router.query.slug || []
+  const slug = (router.query.slug as string[]) || []
 
   return (
     <>

examples/catch-all-routes/pages/index.js renamed to examples/catch-all-routes/pages/index.tsx

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "lib": ["dom", "dom.iterable", "esnext"],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": false,
+    "forceConsistentCasingInFileNames": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true
+  },
+  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
+  "exclude": ["node_modules"]
+}