[Bug] getters have bad formatting

jsonparser.cpp has logic errors and issues with getters

The getters should be something like

```c
double JsonValue::getNumber() const {
if (std::holds_alternative(value_)) { // Was checking for bool
return std::get(value_);
}
throw std::runtime_error("Cannot retrieve number value, types mismatch");
}

const JsonArray& JsonValue::getArray() const {
if (std::holds_alternative(value_)) { // Was checking for bool
return std::get(value_);
}
throw std::runtime_error("Cannot retrieve array value, types mismatch");
}

const JsonObject& JsonValue::getObject() const {
if (std::holds_alternative(value_)) { // Was checking for bool
return std::get(value_);
}
throw std::runtime_error("Cannot retrieve object value, types mismatch");
}
```