Fix Underline <FormatButton /> in `Hovering Toolbar Example` (#4128)
Fix Underline <FormatButton /> in `Hovering Toolbar Example` (#4128)

* Fix Underline <FormatButton /> in `Hovering Toolbar Example`

* Update hovering-toolbar.tsx

Co-authored-by: Ian Storm Taylor <57a33a5496950fec8433e4dd83347673459dcdfc@ianstormtaylor.com>
ianstormtaylor/slate,ianstormtaylor/slate