Allows you to set the help text of the wizard.

	// C#
	// Creates a simple Wizard window and prints the HelpString
	// in the Wizard window.
	using UnityEngine;
	using UnityEditor;
		
	public class HelpString : ScriptableWizard {
		
		[MenuItem ("Example/Show Help String")]
		static void CreateWindow() {
			ScriptableWizard.DisplayWizard("", typeof(HelpString), "Finish");	
		}
		void OnWizardUpdate() {
			helpString = "This string describes what the Scriptable Wizard does.";
		}
	}