[B] Fixes the EXTREME_HILLS_EDGE biome not being included in org.bukkit.block.Biome. Fixes BUKKIT-5433

The Issue:

This PR is meant to be addressing EXTREME_HILLS_EDGE biome not being included in org.bukkit.block.Biome.

Justification for this PR:

Without this change the biome EXTREME_HILLS_EDGE cannot be found in
the Biome class.  This is a problem because if a plugin developer wants to
get a list of all biomes that exist his list would be inaccurate.  This could make a command that is changing to or getting info of a EXTREME_HILLS_EDGE not preform the correct logic. 

PR Breakdown:

This PR adds EXTREME_HILLS_EDGE to org.bukkit.block.Biome.

Testing Results and Materials:

To test my fix I created a simple plugin that when enabled gets the enum constants of Biome and uses a simple foreach to print out all of the values.

JIRA Ticket:

BUKKIT-5433 - https://bukkit.atlassian.net/browse/BUKKIT-5433