I tried to follow along to his tutorial, but when I got to the end and tried to test it out for myself, it would not load properly. It keeps the same error messages, and none of Eclipse's quickfixes help or seem to affect anything whatsoever. I don't know what to do and would appreciate any help. The error message it gives is:
The method register(String, Supplier<? extends I>) in the type DeferredRegister<Item> is not applicable for the arguments (String, Supplier<capture#2-of ? extends I>)