Add sidebar highlight and fix link

Improve appearance of integration of Confluence.

Changelog: fixed

app/views/projects/confluences/show.html.haml

@@ -6,9 +6,8 @@
     = s_('WikiEmpty|Confluence is enabled')
   %p
     - wiki_confluence_epic_link_url = 'https://gitlab.com/groups/gitlab-org/-/epics/3629'
-    - wiki_confluence_epic_link_start = format('<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe, url: wiki_confluence_epic_link_url)
-    = format(s_("WikiEmpty|You've enabled the Confluence Workspace integration. Your wiki will be viewable directly within Confluence. We are hard at work integrating Confluence more seamlessly into GitLab. If you'd like to stay up to date, follow our %{wiki_confluence_epic_link_start}Confluence epic%{wiki_confluence_epic_link_end}.").html_safe, wiki_confluence_epic_link_start: wiki_confluence_epic_link_start, wiki_confluence_epic_link_end: '</a>'.html_safe)
+    - wiki_confluence_epic_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: wiki_confluence_epic_link_url }
+    = html_escape(s_("WikiEmpty|You've enabled the Confluence Workspace integration. Your wiki will be viewable directly within Confluence. We are hard at work integrating Confluence more seamlessly into GitLab. If you'd like to stay up to date, follow our %{wiki_confluence_epic_link_start}Confluence epic%{wiki_confluence_epic_link_end}.")) % { wiki_confluence_epic_link_start: wiki_confluence_epic_link_start, wiki_confluence_epic_link_end: '</a>'.html_safe }
   = link_to @project.confluence_integration.confluence_url, target: '_blank', rel: 'noopener noreferrer', class: 'gl-button btn btn-success external-url', title: s_('WikiEmpty|Go to Confluence') do
-    = sprite_icon('external-link')
     = s_('WikiEmpty|Go to Confluence')
-
+    = sprite_icon('external-link')

lib/sidebars/projects/menus/confluence_menu.rb

@@ -37,6 +37,11 @@ module Sidebars
         def render?
           context.project.has_confluence?
         end
+
+        override :active_routes
+        def active_routes
+          { controller: :confluences }
+        end
       end
     end
   end

spec/features/projects/confluence/user_views_confluence_page_spec.rb

@@ -16,9 +16,12 @@ RSpec.describe 'User views the Confluence page' do
 
     visit project_wikis_confluence_path(project)
 
+    expect(page).to have_css('.nav-sidebar li.active', text: 'Confluence', match: :first)
+
     element = page.find('.row.empty-state')
 
     expect(element).to have_link('Go to Confluence', href: service.confluence_url)
+    expect(element).to have_link('Confluence epic', href: 'https://gitlab.com/groups/gitlab-org/-/epics/3629')
   end
 
   it 'does not show the page when the Confluence integration disabled' do