mitigated include-what-you-use warnings (#330)

Author: firewave

simplecpp.cpp

@@ -14,19 +14,19 @@
 #include <cassert>
 #include <cctype>
 #include <climits>
-#include <cstddef>
+#include <cstddef> // IWYU pragma: keep
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <ctime>
 #include <exception>
-#include <fstream> // IWYU pragma: keep
+#include <fstream>
 #include <iostream>
 #include <limits>
 #include <list>
 #include <map>
 #include <set>
-#include <sstream> // IWYU pragma: keep
+#include <sstream>
 #include <stack>
 #include <stdexcept>
 #include <string>