Advancement for finding specifically a Mushroom Biome.

This advancement would make it clear to new players that stumble on one at random that this is one of the Rarest Biomes in the game. The Type of Advancement for this would be the "Challenge" (Plays music and gives Xp). The Title for it would be "An Extra Side of Shrooms" The Icon would be a Mycelium Block and the Description would be "Stumble into one of the Rarest known Biomes!" Getting the Advancement would reward the player with 175 Experience Points.