Merge branch 'dz-improve-mr-versions' into 'master'

Fix duplicate master entries in the mr versions dropdown

## What does this MR do?

Fixes bug when "master" was duplicated per each mr version in the dropdown

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/22519, Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/22715

See merge request !6567

CHANGELOG

@@ -19,6 +19,7 @@ v 8.12.2 (unreleased)
   - Fix errors importing project feature and milestone models using GitLab project import
   - Make JWT messages Docker-compatible
   - Fix an issue with the "Commits" section of the cycle analytics summary. !6513
+  - Fix duplicate branch entry in the merge request version compare dropdown
 
 v 8.12.1
   - Fix a memory leak in HTML::Pipeline::SanitizationFilter::WHITELIST

app/views/projects/merge_requests/show/_versions.html.haml

@@ -58,11 +58,11 @@
                       .monospace #{short_sha(merge_request_diff.head_commit_sha)}
                       %small
                         = time_ago_with_tooltip(merge_request_diff.created_at)
-                  %li
-                    = link_to merge_request_version_path(@project, @merge_request, @merge_request_diff), class: ('is-active' unless @start_sha) do
-                      %strong
-                        #{@merge_request.target_branch} (base)
-                      .monospace #{short_sha(@merge_request_diff.base_commit_sha)}
+                %li
+                  = link_to merge_request_version_path(@project, @merge_request, @merge_request_diff), class: ('is-active' unless @start_sha) do
+                    %strong
+                      #{@merge_request.target_branch} (base)
+                    .monospace #{short_sha(@merge_request_diff.base_commit_sha)}
 
     - unless @merge_request_diff.latest? && !@start_sha
       .comments-disabled-notif.content-block