"Unknown" displayName values

[jeromecovington]

Thanks for releasing this plugin. I've added it to my build process and most of the components in my tree are being assigned the displayName I would expect. However, there are a number that get assigned a displayName of "Unknown". I've searched through the source for this plugin and don't see a condition under which that value would be explicitly assigned. So, now I've started digging into the handbook for writing babel plugins to see if that is a behavior of babel that is manifesting as "Unknown" once it interacts with this specific plugin. I'd be happy to take a stab at fixing this in a PR, but I'd appreciate some guidance if this issue is already known.