The buttons on the wiki comments page are not styled appropriately

Log in as the admin. Create a course. Enrol a student in the course. Add a wiki activity. Click on the wiki. Select the 'NWiki' format for the first page and save. Click on the 'Comments' tab. Click 'Add comment'. Ensure the buttons are styled with the 'btn' and 'btn-secondary' class. Add a comment. Click to delete the comment. Confirm the 'Yes' and 'No' buttons are styled with the 'btn' and 'btn-secondary' class. Open another browser. Log in as the student. Click on the wiki. Click on the 'Edit' tab. Go back to the browser where you are the admin. Click on the 'Edit' tab. Ensure the 'Override locks' button is styled with the 'btn' and 'btn-secondary' class. As the student make an edit and save. As the admin edit the page and make more changes. Click on the 'History' tab. Click 'Compare selected' to compare two versions. On that page click on the link 'Restore'. Confirm the 'Yes' and 'No' buttons are styled with the 'btn' and 'btn-secondary' class.