Dico-api

Fixed problems with splitter.

Implemented converter.

Implemented autocomplete support at addon.

Fixed type hint.
Allowed prefix function to return list of str.
Fixed bot may respond to the bot.

Added `Addon.on_addon_interaction_error`.
Fixed issues with subcommand.

Added overridable functions to Addon:
Addon.on_load
Addon.on_unload
Addon.on_addon_command_error
Addon.addon_check

Added new decorator on Command:
Command.on_error

Note that on_addon_command_error and on_error must return True or some objects that is True to stop error handling, otherwise main error handler will be called. (This is intended btw.)