ErrorFormatter
Render errors we encounter in a human-readable format so that they are readable for developers and users on failure.
format_arg_extract_err : ArgExtractErr -> Str
Render ArgExtractErr errors as readable messages.
Used in Cli.parse_or_display_message.
format_cli_validation_err : CliValidationErr -> Str
Render CliValidationErr errors as readable messages.
Displayed as the crash message when Cli.assert_valid fails.