Update how-to-insert-a-comment-into-a-word-processing-document.md

Change id calculation method

Author: andreygolubkow

docs/how-to-insert-a-comment-into-a-word-processing-document.md

@@ -115,9 +115,7 @@ creates one using the [AddNewPart\<T\>()](https://msdn.microsoft.com/en-us/libra
             document.MainDocumentPart.WordprocessingCommentsPart.Comments;
         if (comments.HasChildren)
         {
-            id = comments.Descendants<Comment>().Select(e => e.Id.Value).Max();
-            var i = Int32.Parse(id);
-            id = (++i).ToString();
+            id = (comments.Descendants<Comment>().Select(e => int.Parse(e.Id.Value)).Max() + 1).ToString();
         }
     }
     else
@@ -280,9 +278,7 @@ Following is the complete sample code in both C\# and Visual Basic.
                 if (comments.HasChildren)
                 {
                     // Obtain an unused ID.
-                    id = comments.Descendants<Comment>().Select(e => e.Id.Value).Max();
-                    var i = Int32.Parse(id);
-                    id = (++i).ToString();
+                    id = (comments.Descendants<Comment>().Select(e => int.Parse(e.Id.Value)).Max() + 1).ToString();
                 }
             }
             else