This is what works for me on AEM 6.4:
replacing siteName with your site/project name. This is to namespace the style so that it doesn't affect other projects on the instance
form[action*="/content/siteName"] coral-panel-content div.rte-ui coral-buttongroup {
visibility: visible !important;
}
// to hide the additional tooltip (may not be required for all projects)
form[action*="/content/siteName"] div.cq-RichText.richtext-container.coral-Form-field.coral-DecoratedTextfield + coral-tooltip{
visibility: hidden;
}
Good Luck...