the final rename

src/coders/json.cpp

@@ -1,13 +1,13 @@
-#include "json.h"
+#include "json.hpp"
+
+#include "../data/dynamic.hpp"
+#include "../util/stringutil.hpp"
 
 #include <math.h>
 #include <sstream>
 #include <iomanip>
 #include <memory>
 
-#include "../data/dynamic.h"
-#include "../util/stringutil.hpp"
-
 using namespace json;
 using namespace dynamic;