ShinColle-kai

## Polymetallic Ore Generation

Polymetallic Ore now generates in the deepslate layer. Its height range was carried over from ShinColle 1.10.2, where the world bottom was Y 0, so the ore almost never appeared below Y 0.

- Lowered the bottom of the generation range from Y 3 to Y -61 (the top stays at Y 50)
- Generation attempts increased from 7 to 20 per chunk, so it is now slightly more common than iron below Y 72
- The most common height moved from about Y 26 to about Y -5; above about Y 19 it is less common than before
- Ore in deepslate uses the regular Polymetallic Ore block; there is no deepslate variant
- Only newly generated chunks use the new distribution