Remove derived JSON instances for Type

[natefaubion]

#3484 added annotations to Type which technically breaks compatibility since the JSON instances are derived. We should remove these and do something similar to what we've done with the Kind codecs before the next release.

[hdgarrood]

refs #2655

[natefaubion]

What is the status on using aeson-better-errors vs just aeson? The kind codecs use better-errors, but things like corefn just use aeson. Is there a preference?

[hdgarrood]

aeson-better-errors only deals with the parsing direction; I think we generally use standard aeson for producing json, and aeson-better-errors for parsing it. The ide code seems to use standard aeson for both directions, though. There's not any huge reason to prefer one over the other these days, I don't think, as a little while after I first released aeson-better-errors, aeson's own errors improved to be more or less on par with it. The one thing I would say is that I think aeson-better-errors' API is a bit better suited for hand-written instances.