reference correct span parameter name

[ericksoen]

The current behavior when using the provided example returns the following error message: Error: unknown flag: --system

Update the example docs to use the correct parameter name (see documentation for span parameters):

func addSpanParams(cmd *cobra.Command) {
	// --name / -s
	cmd.Flags().StringVarP(&config.SpanName, "name", "s", defaults.SpanName, "set the name of the span")
	// --service / -n
	cmd.Flags().StringVarP(&config.ServiceName, "service", "n", defaults.ServiceName, "set the name of the application sent on the traces")
...
}

[tobert]

Thank you!