docs: update file structure (#71951)

## Summary
Sync
[`04-functions`](https://github.com/vercel/next.js/tree/canary/docs/02-app/02-api-reference/04-functions)
and
[`01-routing`](https://github.com/vercel/next.js/tree/canary/docs/02-app/01-building-your-application/01-routing)
file convention.

### Improving Documentation

- [x] Run `pnpm prettier-fix` to fix formatting issues before opening
the PR.
- [x] Read the Docs Contribution Guide to ensure your contribution
follows the docs guidelines:
https://nextjs.org/docs/community/contribution-guide

Co-authored-by: Delba de Oliveira <32464864+delbaoliveira@users.noreply.github.com>

docs/05-community/01-contribution-guide.mdx

@@ -72,20 +72,20 @@ The file structure reflects the navigation that you see on the site, and by defa
 For example, in the [functions API Reference](/docs/app/api-reference/functions), the pages are sorted alphabetically because it makes it easier for developers to find a specific function:
 
 ```txt
-03-functions
+04-functions
+├── cacheTag.mdx
+├── connection.mdx
 ├── cookies.mdx
-├── draft-mode.mdx
-├── fetch.mdx
 └── ...
 ```
 
 But, in the [routing section](/docs/app/building-your-application/routing), the files are prefixed with a two-digit number, sorted in the order developers should learn these concepts:
 
 ```txt
-02-routing
+01-routing
 ├── 01-defining-routes.mdx
-├── 02-pages-and-layouts.mdx
-├── 03-linking-and-navigating.mdx
+├── 02-pages.mdx
+├── 03-layouts-and-templates.mdx
 └── ...
 ```