SPL-45573 SPL-46389 Improve usage message for the ShepCLI.
SPL-45573 SPL-46389 Improve usage message for the ShepCLI.

splunk/splunk-shuttl,splunk/splunk-shuttl,splunk/splunk-shuttl,splunk/splunk-shuttl,splunk/splunk-shuttl,splunk/splunk-shuttl