Add the tooltip button property to all buttons with short help text, [following this example](https://stackoverflow.com/questions/40017915/tinymce-plugin-show-a-tooltip-on-an-element/#answer-52979043). Especially useful on delete, for explaining what to highlight, e.g. "Delete selected superscript and note" https://github.com/DigitalCarleton/OmekaFootnotesJS/blob/ec3137ad3e01035abd40675cb6364511c671a511/views/admin/javascripts/OmekaFootnotes.js#L19