Make "New issue" button in Issue page less obtrusive (!5457)

CHANGELOG

@@ -27,6 +27,7 @@ v 8.11.0 (unreleased)
   - Bump gitlab_git to speedup DiffCollection iterations
   - Make branches sortable without push permission !5462 (winniehell)
   - Check for Ci::Build artifacts at database level on pipeline partial
+  - Make "New issue" button in Issue page less obtrusive !5457 (winniehell)
   - Add GitLab Workhorse version to admin dashboard (Katarzyna Kobierska Ula Budziszewska)
   - Add the `sprockets-es6` gem
   - Multiple trigger variables show in separate lines (Katarzyna Kobierska Ula Budziszewska)

app/views/help/ui.html.haml

@@ -189,7 +189,7 @@
             %li
               %a Sort by date
 
-        = link_to 'New issue', '#', class: 'btn btn-new'
+        = link_to 'New issue', '#', class: 'btn btn-new btn-inverted'
 
   .lead
     Only nav links without button and search

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

@@ -38,7 +38,7 @@
               %li
                 = link_to 'Edit', edit_namespace_project_issue_path(@project.namespace, @project, @issue)
         - if can?(current_user, :create_issue, @project)
-          = link_to new_namespace_project_issue_path(@project.namespace, @project), class: 'hidden-xs hidden-sm btn btn-grouped new-issue-link btn-success', title: 'New issue', id: 'new_issue_link' do
+          = link_to new_namespace_project_issue_path(@project.namespace, @project), class: 'hidden-xs hidden-sm btn btn-grouped new-issue-link btn-new btn-inverted', title: 'New issue', id: 'new_issue_link' do
             New issue
         - if can?(current_user, :update_issue, @issue)
           = link_to 'Reopen issue', issue_path(@issue, issue: { state_event: :reopen }, status_only: true, format: 'json'), data: {no_turbolink: true}, class: "hidden-xs hidden-sm btn btn-grouped btn-reopen #{issue_button_visibility(@issue, false)}", title: 'Reopen issue'