Merge branch '36061-mr-ref' into 'master'

Instrument MergeRequest#ensure_ref_fetched

See merge request !13876

changelogs/unreleased/36061-mr-ref.yml

+---
+title: Instrument MergeRequest#ensure_ref_fetched
+merge_request:
+author:
+type: other

config/initializers/8_metrics.rb

@@ -119,6 +119,9 @@ def instrument_classes(instrumentation)
 
   # Needed for https://gitlab.com/gitlab-org/gitlab-ce/issues/30224#note_32306159
   instrumentation.instrument_instance_method(MergeRequestDiff, :load_commits)
+
+  # Needed for https://gitlab.com/gitlab-org/gitlab-ce/issues/36061
+  instrumentation.instrument_instance_method(MergeRequest, :ensure_ref_fetched)
 end
 # rubocop:enable Metrics/AbcSize