- Added the config entry 'snake.action-bar' to allow a way to show the score during a snake game
- Changed the error-no-arenas-available config message to clarify that no arenas are open, not that none are set up.
- Made small changes to config comments to be more clarifying

This update adds the following line to the config:
You can add the line to the 'snake' section of the config with indenting before the 'action-bar' text.