Melanoid Axolotls

Replaces the fictional rare blue axolotl with the real life melanistic coloration!

Why?

• I have owned two melanoid axolotls and I want to represent them in the game :3
• The existence of the blue axolotl in Minecraft has unfortunately lead to an increase of dyed blue axolotls in the real life pet trade, the act of which is a harmful to these axolotls. I know Mojang likely didn't intend this and just wanted a fun easter egg, but it's a side effect that disheartens me.