Replace all navigation menu with nav-links class

app/assets/stylesheets/framework/blocks.scss

app/assets/stylesheets/framework/mobile.scss

app/assets/stylesheets/framework/nav.scss

app/assets/stylesheets/framework/sidebar.scss

app/assets/stylesheets/pages/detail_page.scss

app/assets/stylesheets/pages/diff.scss

app/assets/stylesheets/pages/issuable.scss

app/assets/stylesheets/pages/merge_requests.scss

app/assets/stylesheets/pages/projects.scss

app/views/admin/builds/index.html.haml

app/views/dashboard/_activities.html.haml

app/views/dashboard/_activity_head.html.haml

app/views/dashboard/_groups_head.html.haml

app/views/dashboard/_projects_head.html.haml

app/views/dashboard/_snippets_head.html.haml

app/views/dashboard/milestones/show.html.haml

app/views/dashboard/snippets/index.html.haml

app/views/groups/milestones/show.html.haml

app/views/groups/show.html.haml

app/views/help/ui.html.haml