Add some more comments

Source/cmWin32ProcessExecution.h

@@ -23,6 +23,11 @@
  * Written by Bill Tutt <[email protected]>.  Minor tweaks
  * and 2.0 integration by Fredrik Lundh <[email protected]>
  * Return code handling by David Bolen <[email protected]>.
+ *
+ * Modified for CMake.
+ *
+ * For more information, please check Microsoft Knowledge Base
+ * Articles Q190351 and Q150956.
  */
 
 #include "cmStandardIncludes.h"