include(): Use lower case and () to refer to the include() command.

Source/cmIncludeCommand.cxx

@@ -19,7 +19,7 @@ bool cmIncludeCommand
   if (args.size()< 1 || args.size() > 4)
     {
       this->SetError("called with wrong number of arguments.  "
-                     "Include only takes one file.");
+                     "include() only takes one file.");
       return false;
     }
   bool optional = false;