Move discussion button to its own file

Also customizes the message for the “Comment” option to match the current noteable

app/views/projects/notes/_comment_type_button.html.haml

+.btn-group.append-right-10.comment-type-dropdown.js-comment-type-dropdown
+  %button.btn.btn-nr.btn-create.comment-btn.js-comment-button.js-comment-submit-button
+    Comment
+  - if @note.can_be_discussion_note?
+    = button_tag type: 'button', class: 'btn btn-nr dropdown-toggle comment-btn js-note-new-discussion', data: { 'dropdown-trigger' => '#resolvable-comment-menu' } do
+      = icon('caret-down')
+    %ul#resolvable-comment-menu.dropdown-menu{ data: { dropdown: true } }
+      %li#comment{ data: { value: '', 'button-text' => 'Comment', 'secondary-button-text' => 'Comment & close merge request' }, class: 'droplab-item-selected' }
+        = icon('check')
+        .description
+          %strong Comment
+          %p= "Add a general comment to this #{@note.noteable_type.titleize.downcase}."
+      %li.divider
+      %li#discussion{ data: { value: 'DiscussionNote', 'button-text' => 'Start discussion', 'secondary-button-text' => 'Start discussion & close merge request' } }
+        = icon('check')
+        .description
+          %strong Start discussion
+          %p Discuss a specific suggestion or question that needs to be resolved.

app/views/projects/notes/_form.html.haml

@@ -28,23 +28,7 @@
     .error-alert
 
   .note-form-actions.clearfix
-    .btn-group.append-right-10.comment-type-dropdown.js-comment-type-dropdown
-      = f.submit 'Comment', class: "btn btn-nr btn-create comment-btn js-comment-button js-comment-submit-button"
-      - if @note.can_be_discussion_note?
-        = button_tag type: 'button', class: 'btn btn-nr dropdown-toggle comment-btn js-note-new-discussion', data: { 'dropdown-trigger' => '#resolvable-comment-menu' } do
-          = icon('caret-down')
-        %ul#resolvable-comment-menu.dropdown-menu{ data: { dropdown: true } }
-          %li#comment{ data: { value: '', 'button-text' => 'Comment', 'secondary-button-text' => 'Comment & close merge request' }, class: 'droplab-item-selected' }
-            = icon('check')
-            .description
-              %strong Comment
-              %p Add a general comment to this merge request.
-          %li.divider
-          %li#discussion{ data: { value: 'DiscussionNote', 'button-text' => 'Start discussion', 'secondary-button-text' => 'Start discussion & close merge request' } }
-            = icon('check')
-            .description
-              %strong Start discussion
-              %p Discuss a specific suggestion or question that needs to be resolved.
+    = render partial: 'projects/notes/comment_type_button', locals: { show_close_button: true }
 
     = yield(:note_actions)