Disallow options for ModBot commands

Up to now using a word in a ModBot reason argument which started with a
hypen would ModBot not to process the command, as its argparse parser
would consider that word as an not existing option. As we don't use
options and only use arguments for ModBot commands, this disables option
detection for the argparse parser. While this isn't officially supported
by argparse, using a list with `None` as only item for the prefix
characters, which are supposed to be a string instead of a list, does
achieve exactly that.

xpartamupp/modbot.py

@@ -55,6 +55,7 @@ def __init__(self, *args, **kwargs) -> None:
         """
         kwargs["add_help"] = False
         kwargs["exit_on_error"] = False
+        kwargs["prefix_chars"] = [None]
         super().__init__(*args, **kwargs)
         self._positionals = self.add_argument_group("arguments")