Problem with settings a font family
https://developer.sketchapp.com/reference/api/#font

For a persons like me who is not familiar with the Object-c, it's completely unclear how to set a font family with **myNSFont**.

I tried different variants and after a while and some research in source code, only this approach is work for me:
`text._object.setFont(NSFont.fontWithName_size_('PT Sans', 40))`

Sorry If it is not a bug, but it will be great to write in the documentation or show some example how to properly set a font family with the Sketch JS API
`text.font = <what_exactly_we_need_to_set_here>`
