When Content of a StepItem changes, refresh the ItemAnnotations

FindText changed to use StepRTB object

PROMS/Volian.Controls.Library/StepRTB.cs

@@ -1806,7 +1806,7 @@ namespace Volian.Controls.Library
 		private RichTextBoxFinds _FindOptions = RichTextBoxFinds.None;
 		public void FindText(string str, bool caseSensitive, bool matchWholeWord, bool reverse)
 		{
-			StepRTB savRTF = new RTF();
+			StepRTB savRTF = new StepRTB();
 			int startpos = SelectionStart + SelectionLength;
 			savRTF.Text = this.Text;