Make public some casting environment methods

[miyucomics]

I can think of at least a few cases in addons where a person would want to perform their own search of what a casting environment has to offer. Features in base generally shouldn't be done just for addons but I don't see why these very useful methods should be protected and it's currently impossible to access them with usual techniques like invokers because one of the parameters is also a protected enum. Access wideners also don't work because those exclusively only work for base Minecraft classes, not other mods.

[vgskye]

I mean, it's probably possible to use ugly reflection to use these methods, so it's not completely impossible, but yeah LGTM

[object-Object]

hmm, should we count this as a breaking change? it seems like it won't affect existing mod builds, but I think any addon that implements these methods would get a compilation error after this change.