clarifying case senstivity in include order

Author: ArvindReddySheelam

cppguide.html

@@ -399,8 +399,9 @@ <h3 id="Names_and_Order_of_Includes">Names and Order of Includes</h3>
 <p>Include headers in the following order: Related header, C system headers,
 C++ standard library headers,
 other libraries' headers, your project's
-headers.</p>
-
+headers.\b
+The includes should be ordered alphabetically. This ordering should be case-sensitive, meaningthat uppercase and lowercase letters are considered different</p>
+  
 <p>
 All of a project's header files should be
 listed as descendants of the project's source
@@ -6020,4 +6021,4 @@ <h3 id="Windows_Code">Windows Code</h3>
 </ul>
 </div>
 </body>
-</html>
+</html>