Add tooltips to tag buttons

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

@@ -5,17 +5,17 @@
 .gray-content-block
   .pull-right
     - if can?(current_user, :push_code, @project)
-      = link_to edit_namespace_project_tag_release_path(@project.namespace, @project, @tag.name), class: 'btn-grouped btn', title: 'Edit release notes' do
+      = link_to edit_namespace_project_tag_release_path(@project.namespace, @project, @tag.name), class: 'btn-grouped btn has_tooltip', title: 'Edit release notes' do
         = icon("pencil")
-    = link_to namespace_project_tree_path(@project.namespace, @project, @tag.name), class: 'btn btn-grouped', title: 'Browse source code' do
+    = link_to namespace_project_tree_path(@project.namespace, @project, @tag.name), class: 'btn btn-grouped has_tooltip', title: 'Browse files' do
       = icon('files-o')
-    = link_to namespace_project_commits_path(@project.namespace, @project, @tag.name), class: 'btn btn-grouped', title: 'Browse commits' do
+    = link_to namespace_project_commits_path(@project.namespace, @project, @tag.name), class: 'btn btn-grouped has_tooltip', title: 'Browse commits' do
       = icon('history')
     - if can? current_user, :download_code, @project
       = render 'projects/tags/download', ref: @tag.name, project: @project
     - if can?(current_user, :admin_project, @project)
       .pull-right
-        = link_to namespace_project_tag_path(@project.namespace, @project, @tag.name), class: 'btn btn-remove remove-row grouped', method: :delete, data: { confirm: "Deleting the '#{@tag.name}' tag cannot be undone. Are you sure?" } do
+        = link_to namespace_project_tag_path(@project.namespace, @project, @tag.name), class: 'btn btn-remove remove-row grouped has_tooltip', title: "Delete tag", method: :delete, data: { confirm: "Deleting the '#{@tag.name}' tag cannot be undone. Are you sure?" } do
           %i.fa.fa-trash-o
   .title
     %strong= @tag.name