Adds an event handler that runs when the element is double-clicked.
An element receives a dblClick event when a user double-clicks on the element
and releases.
When a user double-clicks an element, two click events are fired
before a doubleClick event is also fired.
handler(event: MouseEvent): void The name of the function or
the function expression to run when the element is clicked.
This method doesn’t return any custom errors, but may return standard errors. Learn more about standard Wix errors.