feat: adapt Endstone 0.9.0 （this version only adapts Endstone 0.9.0+, and does not support older versions）
fix: fix a bug where using the /offhand command while holding item(s) in the offfhand would cause item(s) to diappear
Attention:
Due to changes in the language files, please delete lang dir first, then restart the server to allow the plugin to regenerate it.