FabricDefaultAttributeRegistry#register with an already built DefaultAttributeContainer

[triphora]

Hi,

Is there a possibility of a FabricDefaultAttributeRegistry#register that takes an instance of DefaultAttributeContainer instead of DefaultAttributeContainer.Builder?

Currently the only registering API builds it itself, but this is somewhat inconducive to cross-loader development as Forge's API takes in an already built DefaultAttributeContainer.

I personally cannot see a reason why not to add this - alas I am not experienced with entities, so there could be some other issue with doing this that I cannot see. I am willing to contribute this API myself, but I would rather make sure there aren't any reasons not to do so before spending the time to. :)

[apple502j]

Sounds great, could you PR it or make an issue? @wafflecoffee

[triphora]

Done! #2589