init.lua:
- Added `nether.bottom`
portal.lua:
- Reverted `nether.is_player_in_nether(player)` to previous state.
- Added `nether.is_player_trapped_in_nether(player)`
- Added 2 new chat functions for debugging purposes.
- Tested that chat function `/update_hells_registry` indeed works to check if a player has dug their way out of the nether.
- Moved the functional code from `/update_hells_registry` to `nether.registry_update(player)`
- Fixed some English grammar in automated chat messages.