Closes MR check out branch modal with escape

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

-#modal_merge_info.modal
+#modal_merge_info.modal{ tabindex: '-1' }
   .modal-dialog
     .modal-content
       .modal-header

changelogs/unreleased/45850-close-mr-checkout-modal-on-escape.yml

+---
+title: Closes MR check out branch modal with escape
+merge_request: Jacopo Beschi @jacopo-beschi
+author: 19050
+type: added

spec/features/merge_request/user_sees_check_out_branch_modal_spec.rb

+require 'rails_helper'
+
+describe 'Merge request > User sees Check out branch modal', :js do
+  let(:project) { create(:project, :public, :repository) }
+  let(:user) { project.creator }
+  let(:merge_request) { create(:merge_request, source_project: project) }
+
+  before do
+    sign_in(user)
+    visit project_merge_request_path(project, merge_request)
+    wait_for_requests
+    click_button('Check out branch')
+  end
+
+  it 'shows the check out branch modal' do
+    expect(page).to have_content('Check out, review, and merge locally')
+  end
+
+  it 'closes the check out branch model with Escape keypress' do
+    find('#modal_merge_info').send_keys(:escape)
+
+    expect(page).not_to have_content('Check out, review, and merge locally')
+  end
+end