Feature/new merge breadcrumbs

app/views/projects/merge_requests/creations/new.html.haml

-- breadcrumb_title "Merge Requests"
+- add_to_breadcrumbs "Merge Requests", project_merge_requests_path(@project)
+- breadcrumb_title "New"
 - page_title "New Merge Request"
 
 - if @merge_request.can_be_created && !params[:change_branches]

changelogs/unreleased/50452-breadcrumb-link-to-new-merge-requests.yml

+---
+title: "Fix breadcrumb link to merge requests on new merge request page"
+merge_request: 21502
+author: J.D. Bean
+type: fixed

spec/features/merge_request/user_sees_breadcrumb_links_spec.rb

+require 'rails_helper'
+
+describe 'New merge request breadcrumbs' do
+  let(:project) { create(:project) }
+  let(:user)    { project.creator }
+
+  before do
+    sign_in(user)
+    visit project_new_merge_request_path(project)
+  end
+
+  it 'display a link to project merge requests and new merge request pages' do
+    page.within '.breadcrumbs' do
+      expect(find_link('Merge Requests')[:href]).to end_with(project_merge_requests_path(project))
+      expect(find_link('New')[:href]).to end_with(project_new_merge_request_path(project))
+    end
+  end
+end