docs: fix broken examples link (#86916)

### What?
Fix broken link in the documentation pointing to the examples folder.

### Why?
The previous link to the examples folder in
`docs/04-community/index.mdx` was incorrect:
https://github.com/vercel/next.js/tree/canary/contributing/examples
This caused confusion and 404 errors for contributors trying to access
the correct examples.
(the url page is in here
https://nextjs.org/docs/community/contribution-guide)
### How?
Updated the link in `docs/04-community/index.mdx` to point to the
correct folder:
from 
https://github.com/vercel/next.js/tree/canary/contributing/examples
to
https://github.com/vercel/next.js/tree/canary/examples

Co-authored-by: Joseph <[email protected]>

Author: 2 people

docs/04-community/index.mdx

@@ -11,7 +11,7 @@ With over 5 million weekly downloads, Next.js has a large and active community o
 There are a couple of ways you can contribute to the development of Next.js:
 
 - [Documentation](/docs/community/contribution-guide): Suggest improvements or even write new sections to help our users understand how to use Next.js.
-- [Examples](https://github.com/vercel/next.js/tree/canary/contributing/examples): Help developers integrate Next.js with other tools and services by creating a new example or improving an existing one.
+- [Examples](https://github.com/vercel/next.js/tree/canary/examples): Help developers integrate Next.js with other tools and services by creating a new example or improving an existing one.
 - [Codebase](https://github.com/vercel/next.js/tree/canary/contributing/core): Learn more about the underlying architecture, contribute to bug fixes, errors, and suggest new features.
 
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