fix(docs): update extend repository

[vinhnguyen1211]

• Issue ticket Extended repository example in document is not working #6139
• Update document how to extend repository

[changeset-bot]

⚠️ No Changeset found

Latest commit: afe07ed

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel]

@vinhnguyen1211 is attempting to deploy a commit to the medusajs Team on Vercel.

A member of the Team first needs to authorize it.

[shahednasser]

Thank you for your contribution @vinhnguyen1211 . Can you change the codeblock to match that of this comment?

[vinhnguyen1211]

hi @shahednasser , thanks for your review. I just update following suggestion

[shahednasser]

LGTM! Thank you for your contribution @vinhnguyen1211