Feature request: Add option to change radioButtons appearance similar to actionButtons

[DvP17]

Frequently I (and perhaps other users) try to implement nice looking buttons. As of now, I have to use actionButtons for this. However, as I understand actionButtons are not meant to be selected like radioButtons are but to execute a specific action. In consequence it might be useful to have the option to have the same design/appearance like a clickable button also for radioButtons. In a similar way as its currently implemented by radioButtonsGroup in shinyWidgets.