Remove JsonDocument::data() and JsonDocument::memoryPool()

extras/tests/Misc/Utf8.cpp

@@ -12,7 +12,7 @@ using namespace ARDUINOJSON_NAMESPACE;
 static void testCodepoint(uint32_t codepoint, std::string expected) {
   char buffer[4096];
   MemoryPool pool(buffer, 4096);
-  StringCopier str(pool);
+  StringCopier str(&pool);
   str.startString();
 
   CAPTURE(codepoint);