check for null reference when deleting a source step that has associated enhanced (found during fix for B2016-228)

B2016-228: when creating section/procedure enhanced items, set ‘Number’
B2016-228: when modifying source section or procedure, save ‘Number’ also
B2016-198: User hold point no longer overwrites the ‘INIT/DATE’ signoff heading

PROMS/VEPROMS.CSLA.Library/Generated/ContentInfo.cs

@@ -638,6 +638,14 @@ namespace VEPROMS.CSLA.Library
 						DisplayText dt = new DisplayText(ii, ii.MyContent.Text, false);
 						string str = ItemInfo.Get(tmp.ContentItems[0].ItemID).DisplayTextKeepSpecialChars;
 						dt.Save(str);
+						if (tmp.Type < 20000 && ii.MyContent.Number != tmp.Number)		// update number for sections & procedures, B2016-228
+						{
+							using (Content enhCont = Content.Get(ii.MyContent.ContentID))
+							{
+								enhCont.Number = tmp.Number;
+								enhCont.Save();
+							}
+						}
 					}
 				}
 		}