Update eol-process.md (#16249)

Signed-off-by: Florent Poinsard <[email protected]>

doc/internal/release/eol-process.md

@@ -6,7 +6,8 @@ To properly deprecate a major of Vitess follow the following steps:
 - **Update the website documentation**
   > - In the ['Releases' documentation](https://vitess.io/docs/releases/), the EOL version must be moved under the ['Archived Releases' section](https://vitess.io/docs/releases/#archived-releases).
   > - The sidebar of the website must be changed. We need to remove the EOL version from it. To do so, we move the version folder onto the `archive` folder.
+  > - Add a redirect from the old URL to the new URL in `./layouts/index.redirects` under the `Redirect archived docs` section.
 - **Delete the `Backport To: ...` label**
   > - Delete the corresponding label for the EOL version, we do not want to motivate anymore backport to the EOL release branch.
 - **Make proper announcement on Slack**
-  > - Notify the community of this deprecation. 
+  > - Notify the community of this deprecation.