Do not assume index

Author: QilongTang

src/DynamoCoreWpf/UI/GuidedTour/CustomRichTextBox.cs

@@ -117,8 +117,8 @@ private static FlowDocument GetCustomDocument(string Text)
                         //Finding the end character that indicates the hyperlink is complete (no empty spaces are allowed in hyperlink URL just in the name)
                         if (word.Contains("="))
                         {
-                            string linkURL = word.Split('=')[1];
-                            hyperlinkName += word.Split('=')[0];
+                            string linkURL = word.Split('=').LastOrDefault();
+                            hyperlinkName += word.Split('=').FirstOrDefault();
 
                             Run run3 = new Run(hyperlinkName.Replace("#", ""));
                             Hyperlink link = new Hyperlink(run3);