Safe Transformer Types

[Su5eD]

The issue

Currently, modlauncher determines the type of ITransformers at runtime by getting their generic T type. However, this fails when the interface is implemented in a parent class.

See also:

• Modlauncher can't detect interfaces of transformer parents #97
• Coremods transformer class hierarchy

Trouble with generics

To address the generics issue, we'll use even more generics.
We can't use bounded types because ASM Nodes don't share a common parent, and enums aren't an option either since they can't have generic parameters.

The solution

So, we'll introduce a transformer type class whose generic T type must correspond to the transformer's T type. And by making it a "fake enum" with predefined instances we can effectively limit ITransformer to those types.
This type is then returned from the transformer in a new getTargetType method.

Important disclaimer: This PR introduces BREAKING changes

[cpw]

This will probably have to wait for the 1.19 release cycle, because it's a deeply breaking change.

[cpw]

This is a substantial change. What does it give us? Does it address any key bugs?

[cpw]

This will be modlauncher 11. new major number. We'll need to update the entire stack.

[cpw]

We might need to make sure we have backward compatibility due to problems with tech like mixins, which will require significant refactors to land on this.

[cpw]

letsroll

[cpw]

ye