Fixes main https://gitlab.com/gitlab-org/gitlab/-/issues/30430 by not creating detached head

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

@@ -32,12 +32,12 @@
           - if @merge_request.for_fork?
             :preserve
               git fetch origin
-              git checkout "origin/#{h @merge_request.target_branch}"
+              git checkout "#{h @merge_request.target_branch}"
               git merge --no-ff "#{h @merge_request.source_project_path}-#{h @merge_request.source_branch}"
           - else
             :preserve
               git fetch origin
-              git checkout "origin/#{h @merge_request.target_branch}"
+              git checkout "#{h @merge_request.target_branch}"
               git merge --no-ff "#{h @merge_request.source_branch}"
         %p
           %strong Step 4.