Fix "how to checkout MR" help link

app/views/projects/merge_requests/_how_to_merge.html.haml

@@ -53,4 +53,4 @@
           %strong Tip:
           = succeed '.' do
             You can also checkout merge requests locally by
-            = link_to 'following these guidelines', help_page_path('user/project/merge_requests/index.md', anchor: "checkout-merge-requests-locally"), target: '_blank', rel: 'noopener noreferrer'
+            = link_to 'following these guidelines', help_page_path('user/project/merge_requests/reviewing_and_managing_merge_requests.md', anchor: "checkout-merge-requests-locally"), target: '_blank', rel: 'noopener noreferrer'

changelogs/unreleased/fix-how-to-checkout-mr-link.yml

+---
+title: Fix "how to checkout MR" help link
+merge_request: 31688
+author:
+type: fixed