clean up includes

src/parser.cpp

@@ -1,10 +1,9 @@
-#include <iostream>
-#include <cctype>
-#include <cstring>
-#include <memory>
-#include <vector>
 #include "expression.hpp"
 #include "print.h"
+#include <cctype>
+#include <cstring>
+#include <iostream>
+#include <vector>
 
 namespace Parser {