[deserialize] Unicode escape "\u0000" is silently ignored

Created by: bupjae

ArduinoJson version: v6.18.3 Target platform: x86-64 Toolchain: gcc (x86_64-posix-seh-rev0, Built by MinGW-W64 project) 8.1.0

Code snippet:

#include <iostream>
#include <string>

#include "ArduinoJson-v6.18.3.hpp"

using namespace std;
using namespace ArduinoJson;

int main() {
  StaticJsonDocument<1024> doc;
  cout << deserializeJson(doc, R"({"data": "wx\u0000yz"})") << endl;
  string value = doc["data"];
  cout << value << endl;
  cout << value.length() << endl;
}

Excepted result (NUL character is replaced to '_' for visibility):

Ok
wx_yz
5

Actual result:

Ok
wxyz
4

I understand that NUL character inside string is very hard to handle for C/C++ code. However, I think this behavior should be documented at least.