Fix for bug #99517: Text migrates past H. Line, loses formatting when converted to list

Modified WillMakeList() to clear prevListItem after adding a block
to a list item so that any inline nodes after the block are put
in a new list item.

r=jfrancis@netscape.com  sr=sfraser@netscape.com

editor/libeditor/html/nsHTMLEditRules.cpp

@@ -2403,6 +2403,8 @@ nsHTMLEditRules::WillMakeList(nsISelection *aSelection,
         if (NS_FAILED(res)) return res;
         if (IsInlineNode(curNode)) 
           prevListItem = listItem;
+        else
+          prevListItem = nsnull;
       }
     }
     else