* Introduce CommandSender.getLocale()
This allows Geyser-specific commands (e.g. `/geyser help`) to be displayed in the (Java or Bedrock) player's default language, which stops those commands from simply being displayed in the default locale.
* Tweak Javadoc
* Set CommandManager's GeyserConnector to final
* Clean up
- Added `GeyserCommand.isExecutableOnConsole()`. If this is set to false, the command will not appear as an option in the GUI.
- Added `GeyserCommand.getSubCommands()`. If not empty, the subcommand options will now appear in the GUI.