Explicitly releases the binding between the source and the target.
This function will release the reference that is being held on this if the binding is still bound; if you want to hold on to the binding instance after calling this method, you will need to manually hold a reference to it.
Note that this function does not take ownership of this, it only unrefs the instance that was initially created by [func@Adw.bind_property_to_css_class] and is owned by the binding.
| this |
a binding |