clang-tidy: fixed "uninitialized field" in VariantData

src/ArduinoJson/Document/JsonDocument.hpp

@@ -32,7 +32,7 @@ class JsonDocument : public Visitable {
 
   void clear() {
     _pool.clear();
-    _data.setNull();
+    _data.init();
   }
 
   template <typename T>
@@ -304,15 +304,15 @@ class JsonDocument : public Visitable {
 
  protected:
   JsonDocument() : _pool(0, 0) {
-    _data.setNull();
+    _data.init();
   }
 
   JsonDocument(MemoryPool pool) : _pool(pool) {
-    _data.setNull();
+    _data.init();
   }
 
   JsonDocument(char* buf, size_t capa) : _pool(buf, capa) {
-    _data.setNull();
+    _data.init();
   }
 
   ~JsonDocument() {}

src/ArduinoJson/Variant/VariantData.hpp

@@ -33,7 +33,7 @@ class VariantData {
   // - no virtual
   // - no inheritance
   void init() {
-    _flags = 0;
+    _flags = VALUE_IS_NULL;
   }
 
   template <typename TVisitor>